🐛 [RUMF-1060] fix failing worker detection in Firefox

[BenoitZugmeyer]

Motivation

In Firefox, when the worker fails to instanciate because of CSP rules, it doesn't throw an error like Chromium does, but rather emits a error event asynchronously.

Changes

• Make sure we catch error events from the worker
• When creating the worker, check if the communication succeeds by sending an 'init' action and waiting for a 'initialized' response.

Testing

CI, manual

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I have gone over the contributing documentation.

[codecov-commenter]

Codecov Report

Merging #1139 (287d6b0) into main (332724b) will increase coverage by 0.27%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1139      +/-   ##
==========================================
+ Coverage   89.16%   89.44%   +0.27%     
==========================================
  Files          93       93              
  Lines        4201     4253      +52     
  Branches      962      972      +10     
==========================================
+ Hits         3746     3804      +58     
+ Misses        455      449       -6     

Impacted Files	Coverage Δ
packages/core/src/domain/internalMonitoring.ts	95.89% <100.00%> (+0.36%)	⬆️
packages/rum/src/boot/recorderApi.ts	100.00% <100.00%> (ø)
...ckages/rum/src/domain/segmentCollection/segment.ts	100.00% <100.00%> (+2.32%)	⬆️
...src/domain/segmentCollection/startDeflateWorker.ts	100.00% <100.00%> (ø)
packages/rum/test/utils.ts	85.54% <100.00%> (+1.27%)	⬆️
...e/src/domain/configuration/experimentalFeatures.ts	92.30% <0.00%> (-7.70%)	⬇️

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