RUM-6171 use FileObserver to limit calls to filesystem

[0xnm]

What does this PR do?

The same as https://github.com/DataDog/dd-sdk-android/pull/2718, just branch moved directly to the repo.

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

:x: Patch coverage is 91.83673% with 4 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 71.25%. Comparing base (ed7f4e1) to head (a3851b0). :warning: Report is 2 commits behind head on develop.

Files with missing lines	Patch %	Lines
...al/persistence/file/batch/BatchFileOrchestrator.kt	91.84%	0 Missing and 4 partials :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2720      +/-   ##
===========================================
+ Coverage    71.24%   71.25%   +0.01%     
===========================================
  Files          866      866              
  Lines        31730    31742      +12     
  Branches      5360     5364       +4     
===========================================
+ Hits         22604    22615      +11     
+ Misses        7602     7596       -6     
- Partials      1524     1531       +7     

Files with missing lines	Coverage Δ
...al/persistence/file/batch/BatchFileOrchestrator.kt	93.41% <91.84%> (+0.51%)	:arrow_up:

... and 33 files with indirect coverage changes

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[datadog-datadog-prod-us1[bot]]

🎯 Code Coverage
• Patch Coverage: 100.00%
• Overall Coverage: 71.46% (-0.01%)
View detailed report

<sub>This comment will be updated automatically if new data arrives.
* Fix with Cursor requires Datadog plugin ≥v2.17.0
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