refactor: split migrations into multiple files

[dbrans]

Description

Split each migration function and the associated unit tests into separate files.

See the extension approach which also exports the migration version from each individual migration file (example)

Related issues

Fixes: #7845

Manual testing steps

Screenshots/Recordings

Before

After

Pre-merge author checklist

• Run e2e test as smoke test
• Ensure test for migration 25 is unaffected
• I’ve followed MetaMask Coding Standards.
• I've clearly explained what problem this PR is solving and how it is solved.
• I've linked related issues
• I've included manual testing steps
• I've included screenshots/recordings if applicable
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.
• I’ve properly set the pull request status:
  • In case it's not yet "ready for review", I've set it to "draft".
  • In case it's "ready for review", I've changed it from "draft" to "non-draft".

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[github-actions]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[codecov-commenter]

Codecov Report

Attention: 151 lines in your changes are missing coverage. Please review.

Comparison is base (199aa40) 36.60% compared to head (3b2eaed) 36.60%.
Report is 2 commits behind head on main.

Files	Patch %	Lines
app/store/migrations/004.js	0.00%	30 Missing ⚠️
app/store/migrations/007.js	0.00%	18 Missing ⚠️
app/store/migrations/008.js	0.00%	17 Missing ⚠️
app/store/migrations/003.js	0.00%	11 Missing ⚠️
app/store/migrations/013.js	0.00%	11 Missing ⚠️
app/store/migrations/001.js	0.00%	8 Missing ⚠️
app/store/migrations/012.js	0.00%	8 Missing ⚠️
app/store/migrations/000.js	0.00%	7 Missing ⚠️
app/store/migrations/002.js	0.00%	7 Missing ⚠️
app/store/migrations/005.js	0.00%	4 Missing ⚠️
... and 10 more

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7873   +/-   ##
=======================================
  Coverage   36.60%   36.60%           
=======================================
  Files        1092     1120   +28     
  Lines       29178    29178           
  Branches     2677     2678    +1     
=======================================
  Hits        10681    10681           
  Misses      17885    17885           
  Partials      612      612           

☔ View full report in Codecov by Sentry.
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[github-actions]

E2E test started on Bitrise: https://app.bitrise.io/app/be69d4368ee7e86d/pipelines/07d34fed-5d1b-44ed-b8e4-a3267d112211
You can also kick off another Bitrise E2E smoke test by removing and re-applying the (Run Smoke E2E) label

[github-actions]

E2E test started on Bitrise: https://app.bitrise.io/app/be69d4368ee7e86d/pipelines/8bde408d-69af-453e-8898-2d9e03dd3cdf
You can also kick off another Bitrise E2E smoke test by removing and re-applying the (Run Smoke E2E) label

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
9 Code Smells

47.8% Coverage
0.0% Duplication