RUM-6375: Force single core for session replay

[jonathanmos]

What does this PR do?

Allow session replay to run on only one core at a time. Attempting to start sr on more cores will send telemetry.

Motivation

It probably doesn't make sense for session replay to run on multiple cores.

Additional Notes

Anything else we should know when reviewing?

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

Attention: Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 70.37%. Comparing base (992020c) to head (0cf1490).
Report is 3 commits behind head on develop.

Files with missing lines	Patch %	Lines
...tadog/android/core/internal/NoOpInternalSdkCore.kt	0.00%	1 Missing ⚠️
...com/datadog/android/sessionreplay/SessionReplay.kt	90.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2324      +/-   ##
===========================================
- Coverage    70.42%   70.37%   -0.05%     
===========================================
  Files          740      740              
  Lines        27593    27604      +11     
  Branches      4622     4624       +2     
===========================================
- Hits         19430    19425       -5     
- Misses        6878     6888      +10     
- Partials      1285     1291       +6     

Files with missing lines	Coverage Δ
...src/main/kotlin/com/datadog/android/api/SdkCore.kt	25.00% <ø> (ø)
...n/com/datadog/android/core/internal/DatadogCore.kt	82.27% <100.00%> (+0.08%)	⬆️
...tadog/android/core/internal/NoOpInternalSdkCore.kt	8.97% <0.00%> (-0.12%)	⬇️
...com/datadog/android/sessionreplay/SessionReplay.kt	68.42% <90.00%> (+6.35%)	⬆️

... and 28 files with indirect coverage changes