[build-tools] Enable Gradle cache via machine-level gradle.properties to avoid fingerprint mutation

[AbbanMustafa]

Why

Writing org.gradle.caching=true to android/gradle.properties mutates a project file, which affects Expo fingerprinting. This can cause unnecessary cache invalidation and incorrect fingerprint changes. We explored enabling via environment variable #3849 which is still not supported gradle/gradle#18087

How

Enable Gradle build cache by writing to ~/.gradle/gradle.properties (machine-level) instead of android/gradle.properties (project-level). This is functionally equivalent but doesn't touch any project files.

Test Plan

Validated locally and confirmed Gradle cache hits (FROM-CACHE) in the build output, matching the behavior of the current approach.

[github-actions]

Subscribed to pull request

File Patterns	Mentions
**/*	@douglowder

Generated by CodeMention

[github-actions]

⏩ The changelog entry check has been skipped since the "no changelog" label is present.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.40%. Comparing base (f1aa26d) to head (3107a96).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...ild-tools/src/steps/functions/restoreBuildCache.ts	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3852      +/-   ##
==========================================
+ Coverage   58.36%   58.40%   +0.04%     
==========================================
  Files         917      917              
  Lines       39931    39966      +35     
  Branches     8382     8388       +6     
==========================================
+ Hits        23302    23338      +36     
  Misses      15195    15195              
+ Partials     1434     1433       -1     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.