[configure-splash-screen]<chore>: Update test file names to follow naming convention

[chernandez7]

TODO

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• Confirm XML naming convention
• Make sure tests are passing on CircleCI

Description

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As mentioned in issue #2591 and PR #2297, we want to update tests from .test to -test.

Only question I have is relating to the .xml files. Should those also follow the convention mentioned above or stay as xml.test?

Also, it's my first PR towards Expo so if I missed any conventions to follow feel free to let me know.

Test Plan

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I don't believe much testing would be needed since it's just renaming files.

I ran the tests on the package but some were failing and it seems like they're related to my environment or even OS. But would like some confirmation on if that's true or not.

Ex. 1:
  -     "image": "/assets/background.png",
  +     "image": "E:\\assets\\background.png",

Ex. 2:
    -   "image": "/assets/background.png",
    +   "image": "E:\\assets\\background.png",

Ex. 3:
 EEXIST: file already exists, mkdir 'E:\app\android\app\src\main\res\drawable'

      at createError (../../node_modules/memfs/lib/volume.js:121:17)
      at Volume.mkdirBase (../../node_modules/memfs/lib/volume.js:1527:19)
      at Immediate.<anonymous> (../../node_modules/memfs/lib/volume.js:681:39)

[EvanBacon]

You can ensure it works on your machine by running the tests on master.

[bbarthec]

This LGTM 👍
Tests are fired and are passing ✅
I like the .xml naming as you're proposing 😉