[Dependency Cache] Use Custom Init Gradle Task to Download Dependencies

[ParaskP7]

Project Thread: paaHJt-7CE-p2
Test PR: #13387
Depends On: buildkite-ci#585

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Description

This PR uses the custom init.gradle.kts related file, defined within the Android AMI itself (see buildkite-ci#585), which now contains this custom downloadDependencies task.

With this change, instead of individually calling a number of assemble/lint related tasks to download as many dependencies as possible prior to saving the cache, any project can now utilize this globally defined downloadDependencies task to replace all this boilerplate and streamline the overall dependency cache process.

Notably, with this change, the dependency cache process:

1. Will no longer be broken on issues like this, making the process more robust.
2. Will no longer require an associated entry save-cache.sh entry (example) for newly defined jobs/commands, making the process more maintainable.
3. Will no longer have any missing dependencies that would require extra network activity, making the process faster (just a second or two, but faster nevertheless).
4. Will no longer take a significant amount of time to save the cache, as it will no longer run any assemble/lint tasks, just that single downloadDependencies task, making the build process faster (for scheduled builds).

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Testing information

Just verify the below:

1. Triggering schedules/dependency-cache.yml manually via this build:
   • Starts downloading the dependencies.
   • Caches the dependencies successfully.
     • Duration: 48s
     • Size: 784.61 MB
   • Total time it takes for the dependency cache job to complete: 5m 20s
2. CI is working as expected:
   • The cache is restored successfully:
     • Duration: 15s
     • Size: 784.61 MB
   • For that same job via its build scan, that no extra network activity occurs during dependency resolution. Same should apply to all jobs that use restore-cache.sh.

Note

The only drawback to this change, but an expected one, is that the size of the dependency cache is considerably bigger than before, 784.61 MB now, 625.74 MB before, which is more than 150 MB a diff, and this makes the cache restoration a few seconds slower (12s before, 15s now, ish). Having said that, we believe that the low cost of maintaining the cache saving process is worth the extra seconds (context).

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Merge Instructions

• Trigger a schedules/dependency-cache.yml build manually and make sure that it is not working yet (as expected).
  • Build -> Task 'downloadDependencies' not found in root project 'WCAndroid' and its subprojects.
• Wait for buildkite-ci#585 to be reviewed, approved, deployed and merged.
• Trigger another schedules/dependency-cache.yml build manually and make sure everything now works as expected (the new dependency cache is saved).
  • Build -> Saving Gradle dependency cache...
• Trigger a normal pipeline.yml build and make sure everything is working as expected (the new dependency cache is restored).
• Remove status: do not merge label.
• Merge this PR.
• Close [Buildkite] Test Android Staging on ami-0953ca1d949c23a58 -> ami-0f976e0b4de96aa28 #13387 and a8c-ci-toolkit-buildkite-plugin#142
  test-only PRs.

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• I have considered if this change warrants release notes and have added them to RELEASE-NOTES.txt if necessary. Use the "[Internal]" label for non-user-facing changes.

Reviewer (or Author, in the case of optional code reviews):

Please make sure these conditions are met before approving the PR, or request changes if the PR needs improvement:

• The PR is small and has a clear, single focus, or a valid explanation is provided in the description. If needed, please request to split it into smaller PRs.
• Ensure Adequate Unit Test Coverage: The changes are reasonably covered by unit tests or an explanation is provided in the PR description.
• Manual Testing: The author listed all the tests they ran, including smoke tests when needed (e.g., for refactorings). The reviewer confirmed that the PR works as expected on big (tablet) and small (phone) in case of UI changes, and no regressions are added.

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce-Wear Android by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce-Wear Android
	Platform	⌚️ Wear OS
	Flavor	Jalapeno
	Build Type	Debug
	Commit	20c13f9
	Direct Download	woocommerce-wear-prototype-build-pr13391-20c13f9.apk

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce Android by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce Android
	Platform	📱 Mobile
	Flavor	Jalapeno
	Build Type	Debug
	Commit	20c13f9
	Direct Download	woocommerce-prototype-build-pr13391-20c13f9.apk