Replace STORE_NAME usage with named constants

For historical purposes we mix use of STORE_NAME and named constants for modules (like CORE_SITE or MODULES_ANALYTICS). But in files with multiple stores, the unnamed STORE_NAME provides little context, and now that the named constants are also available, we should replace all instances of STORE_NAME with the actual constant name (eg. CORE_SITE, CORE_USER, etc.)

---

Do not alter or remove anything below. The following sections will be managed by moderators only.

Acceptance criteria

• All instances of STORE_NAME throughout the code should be replaced with the “named constant” they represent.
• Any other instances of STORE_NAME (for instance, in create-settings-store.js), should be renamed to something like settingsStoreName so they don’t invoke confusion for current developers because of the historical context of STORE_NAME. Using the constant formatting in this file isn’t really appropriate anyway. 🙂

Implementation Brief

• Replace all instances of STORE_NAME throughout the code with the appropriate named constant for the module.
• Remove the STORE_NAME variables declarations in module constants files like https://github.com/google/site-kit-wp/blob/b6dade1a841d681c1df1f3d6fc5b5378ad5a6652/assets/js/googlesitekit/datastore/location/constants.js#L19, changes it to be export const CORE_LOCATION = 'core/location';
• In places like https://github.com/google/site-kit-wp/blob/b6dade1a841d681c1df1f3d6fc5b5378ad5a6652/assets/js/googlesitekit/data/create-existing-tag-store.test.js#L33 that use a “Test” store/store name, change the variable to TEST_STORE.
• Replace https://github.com/google/site-kit-wp/blob/b6dade1a841d681c1df1f3d6fc5b5378ad5a6652/assets/js/googlesitekit/data/create-settings-store.js#L82 with a variable like settingsStoreName—do the same in other generated stores with an appropriate variable name.

Test Coverage

• N/A

Visual Regression Changes

• N/A

QA Brief

• All unit tests and linting should continue to pass.
• Verify no STORE_NAME constants are used/imported/exported from constants.js files.
• Note that in many create-X-store.js files and tests there will be properties/internal variables with STORE_NAME values—these are separate and since they’re part of the API not worth changing here. They’re also internal and don’t cause the confusion this issue intended to fix 🙂

Changelog entry

• N/A

[wpdarren]

I feel this is a QA:Eng ticket but if I am incorrect then please feel free to let me know!

[asvinb]

• Searched for the STORE_NAME throughout the codebase and no STORE_NAME constants are used/imported/exported from constants.js files. ☑️
• STORE_NAME is only present in create-X-store.js files. ☑️

QA: ✅