Insufficient Funds notification text needs update

Description

Found while testing https://github.com/brave/brave-browser/issues/1479

Insufficient Funds notification references Brave Payments, this text should be updated.

@mandar-brave please provide text for notification.

Steps to Reproduce

1. Launched Brave with - -rewards=reconcile-interval=4340
2. Enable Rewards
3. Visit a site.
4. Wait 15-20 minutes

Actual result:

Notification displays with text referencing Brave Payments:

Expected result:

Notification should probably reference Brave Rewards, but @mandar-brave should provide text to be used.

Reproduces how often:

easily

Brave version (brave://version info)

Brave	0.60.23 Chromium: 72.0.3626.96 (Official Build) beta(64-bit)
Revision	84098ee7ef8622a9defc2ef043cd8930b617b10e-refs/branch-heads/3626@{#836}
OS	Mac OS X

Reproducible on current release:

• Does it reproduce on brave-browser dev/beta builds? yes

Website problems only:

• Does the issue resolve itself when disabling Brave Shields? n/a
• Is the issue reproducible on the latest version of Chrome? n/a

Additional Information

[srirambv]

Marking as Windows and macOS as its still failing on Linux and followup issue(#3786 ) for Linux is logged

[kjozwiak]

cc: @kjozwiak to try on his Linux machine

Reproduced and commented results under https://github.com/brave/brave-browser/issues/3786#issuecomment-474547027.