RUM-2926: Introduce error.category attribute for exceptions, categorize ANRs separately

[0xnm]

What does this PR do?

This PR does the following things:

• Adds error.category attribute, with possible values null|AppHang|ANR|Exception
• Fills the mentioned attribute when error happens using the following logic: if error is ANR, then value is ANR; if error has throwable attached or non-empty stacktrace - Exception; otherwise it is null.

This property allows better high-level organization of error happening in the application.

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

Merging #1918 (f30fd3a) into develop (5d54877) will increase coverage by 0.01%.
Report is 15 commits behind head on develop.
The diff coverage is 92.86%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1918      +/-   ##
===========================================
+ Coverage    83.39%   83.40%   +0.01%     
===========================================
  Files          478      478              
  Lines        17142    17112      -30     
  Branches      2565     2561       -4     
===========================================
- Hits         14295    14272      -23     
+ Misses        2140     2133       -7     
  Partials       707      707              

Files	Coverage Δ
...g/android/rum/internal/DatadogLateCrashReporter.kt	84.97% <100.00%> (-0.32%)	⬇️
.../android/rum/internal/domain/scope/RumViewScope.kt	93.33% <100.00%> (-0.54%)	⬇️
...roid/rum/internal/domain/scope/RumResourceScope.kt	94.20% <80.00%> (-0.63%)	⬇️

... and 22 files with indirect coverage changes

[mariusc83]

I think the best practice is to add the { } here, is it on one single line though ?