Update Ambry to Gradle 7.6.6

[j-tyler]

Summary

The current Gradle version of 5.2.1 is very old. Modernizing the Ambry build speeds up the build and pulls in all the latest and greatest gradle features.

Testing Done

./gradlew allJar
./gradlew build

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.91%. Comparing base (52ba813) to head (0eef832).
⚠️ Report is 328 commits behind head on master.

Files with missing lines	Patch %	Lines
...ub/ambry/cloud/azure/ADAuthBasedStorageClient.java	0.00%	2 Missing ⚠️
...hub/ambry/accountstats/AccountStatsMySqlStore.java	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3178      +/-   ##
============================================
+ Coverage     64.24%   69.91%   +5.66%     
- Complexity    10398    12802    +2404     
============================================
  Files           840      930      +90     
  Lines         71755    78971    +7216     
  Branches       8611     9431     +820     
============================================
+ Hits          46099    55209    +9110     
+ Misses        23004    20837    -2167     
- Partials       2652     2925     +273     

☔ View full report in Codecov by Sentry.
📢 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.