Update Gradle to 8.9 and AGP to 8.5.2

[0xnm]

What does this PR do?

Since we are now using Kotlin 1.9, we can also update Gradle and AGP to the newer versions (which were bringing Kotlin 1.9 to the classpath).

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.99%. Comparing base (6d2cf93) to head (c07bc24).
Report is 11 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2192      +/-   ##
===========================================
- Coverage    70.02%   69.99%   -0.02%     
===========================================
  Files          726      726              
  Lines        27004    26968      -36     
  Branches      4526     4522       -4     
===========================================
- Hits         18907    18876      -31     
+ Misses        6827     6826       -1     
+ Partials      1270     1266       -4     

Files	Coverage Δ
...compat/widget/DatadogActionBarContainerAccessor.kt	100.00% <100.00%> (ø)
...ternal/recorder/mapper/ActionBarContainerMapper.kt	90.48% <ø> (ø)
...main/java/com/datadog/exec/CommonTaskExecutor.java	47.83% <100.00%> (ø)

... and 26 files with indirect coverage changes