inline tipping doesn't work under Twitter

Description

Inline tipping has stopped working under Twitter. When pressing the inline BAT button, you’ll get the following errors in the browser console:

brave_rewards_panel_content_twitter.bundle.js:1 Failed to fetch tweet details for 1204589420617371649: Unexpected end of JSON input
(anonymous) @ brave_rewards_panel_content_twitter.bundle.js:1
Promise.catch (async)
l @ brave_rewards_panel_content_twitter.bundle.js:1
s.onclick @ brave_rewards_panel_content_twitter.bundle.js:1

brave_rewards_panel_content_twitter.bundle.js:1 Failed to fetch tweet metadata for [object HTMLDivElement]: SyntaxError: Unexpected end of JSON input
    at a (brave_rewards_panel_content_twitter.bundle.js:1)
(anonymous) @ brave_rewards_panel_content_twitter.bundle.js:1
Promise.catch (async)
s.onclick @ brave_rewards_panel_content_twitter.bundle.js:1

brave_rewards_panel_content_twitter.bundle.js:1 Cross-Origin Read Blocking (CORB) blocked cross-origin response https://api.twitter.com/1.1/statuses/show.json?id=1204589420617371649 with MIME type application/json. See https://www.chromestatus.com/feature/5629709824032768 for more details.
a @ brave_rewards_panel_content_twitter.bundle.js:1
async function (async)
a @ brave_rewards_panel_content_twitter.bundle.js:1
(anonymous) @ brave_rewards_panel_content_twitter.bundle.js:1
l @ brave_rewards_panel_content_twitter.bundle.js:1
s.onclick @ brave_rewards_panel_content_twitter.bundle.js:1

You’ll get the following errors in the terminal:

[79025:775:1210/223655.310171:INFO:CONSOLE(1)] "Failed to fetch tweet details for 1204604280180789248: Unexpected end of JSON input", source: chrome-extension://jidkidbbcafjabdphckchenhfomhnfma/out/brave_rewards_panel_content_twitter.bundle.js (1)

Seems like something was introduced in C79 that’s causing the issue. Errors in the browser console are mentioning a CORS issue.

Steps to Reproduce

1. install & launch 1.1.20 CR: 79.0.3945.74
2. enable Rewards and login into https://twitter.com/
3. attempt to tip users/tweets via inline tipping

Actual result:

Clicking on the BAT icon via inline won’t do anything and will produce the above errors mentioned above via the browser console and the terminal.

Expected result:

Clicking on the BAT icon via inline on Twitter should display the tipping banner.

Reproduces how often:

100% reproducible when using the above STR.

Brave version (brave://version info)

Brave	1.1.20 Chromium: 79.0.3945.74 (Official Build) (64-bit)
Revision	99b6d241cf84f7fa7434ae8a59f9e74eb1464280-refs/branch-heads/3945@{#888}
OS	macOS Version 10.15.1 (Build 19B88)

Version/Channel Information:

• Can you reproduce this issue with the current release? Reproducible
• Can you reproduce this issue with the beta channel? Reproducible
• Can you reproduce this issue with the dev channel? Reproducible
• Can you reproduce this issue with the nightly channel? Reproducible

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? No, still reproducible
• Does the issue resolve itself when disabling Brave Rewards? N/A
• Is the issue reproducible on the latest version of Chrome? N/A

Miscellaneous Information:

CCing @rebron @bsclifton @brave/legacy_qa @NejcZdovc

[btlechowski]

Verification passed on

Brave	1.1.21 Chromium: 79.0.3945.79 (Official Build) (64-bit)
Revision	29f75ce3f42b007bd80361b0dfcfee3a13ff90b8-refs/branch-heads/3945@{#916}
OS	Windows 7 Service Pack 1 (Build 7601.24530)

Verified test plan from the description and https://github.com/brave/brave-core/pull/4215. Verified that I was able to tip the publisher. Verified that the tip was visible under Tips on brave://rewards

Verification passed on

Brave	1.1.21 Chromium: 79.0.3945.79 (Official Build) (64-bit)
Revision	29f75ce3f42b007bd80361b0dfcfee3a13ff90b8-refs/branch-heads/3945@{#916}
OS	Ubuntu 18.04 LTS

Verified test plan from the description and https://github.com/brave/brave-core/pull/4215. Verified that I was able to tip the publisher. Verified that the tip was visible under Tips on brave://rewards

Verified passed with

Brave	1.1.21 Chromium: 79.0.3945.79 (Official Build) (64-bit)
Revision	29f75ce3f42b007bd80361b0dfcfee3a13ff90b8-refs/branch-heads/3945@{#916}
OS	macOS Version 10.13.6 (Build 17G5019)

• Verified test plan from https://github.com/brave/brave-core/pull/4215

• Verified able to see custom banner data when tipping from panel

• Verified normal banner displayed as well:

• Verified able to tip Twitter publishers from panel and tips displayed in Tips panel on brave://rewards

• Verified in-line tipping for Twitter, Reddit, and GH showed the expected banners (encountered https://github.com/brave/brave-browser/issues/5562 for in-line tipping on GH) and am able to tip on each of these sites:

Verification PASSED on macOS 10.15.1 x64 using the following build:

Brave	1.1.21 Chromium: 79.0.3945.79 (Official Build) (64-bit)
Revision	29f75ce3f42b007bd80361b0dfcfee3a13ff90b8-refs/branch-heads/3945@{#916}
OS	macOS Version 10.15.1 (Build 19B88)

Note: Used Production instead of Staging

• Verified test plan from the description and https://github.com/brave/brave-core/pull/4215.
• Verified that I was able to tip the publisher.
• Verified that the tip was visible under Tips on brave://rewards
• also checked GH & Reddit re: inline tipping

[bsclifton]

Fixed with https://github.com/brave/brave-core/pull/4215

cc: @SergeyZhukovsky @samartnik @AlexeyBarabash RE: the above Android issue