RUM-7806 improve the view duration accuracy

[xgouchet]

What does this PR do?

Use a more accurate view duration : do not update the view duration after the view has been stopped.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.00%. Comparing base (9d727b7) to head (19e004d).
Report is 5 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2467      +/-   ##
===========================================
- Coverage    70.01%   70.00%   -0.01%     
===========================================
  Files          786      786              
  Lines        29298    29302       +4     
  Branches      4890     4891       +1     
===========================================
+ Hits         20511    20512       +1     
- Misses        7430     7435       +5     
+ Partials      1357     1355       -2     

Files with missing lines	Coverage Δ
.../android/rum/internal/domain/scope/RumViewScope.kt	95.26% <100.00%> (+0.02%)	⬆️

... and 22 files with indirect coverage changes