🔈Add web vital attribution telemetry debug

[amortemousque]

Motivation

Assess the best strategy to display / collect the Core Web Vital attributed node.
Here are the questions that need to be answered:

How often do we have the attributed DOM element?
Can we get the serialized node id by the time we process the web vitals?

Answered with the "XXX attribution" telemetry debug:

• hasNode: Check if the web vital has an attributed element to collect
• replayRecording: is Replay recording
• serializedDomNode: Get the serialized DOM node if available
• computationDelay: Delay between the web vital and the collection of the web vital by the SDK

How precise would be a Replay visualization?

Answered with the "XXX attribution recording delay" debug:

• recordingDelay: Delay between the web vital and Replay start
• computationDelay: Delay between the web vital and the collection of the web vital by the SDK
• hasNode: Do we still have the node when replay starts
• serializedDomNode: Can we still get the Node id when replay starts

Changes

• Add recorderStartObservable to RecorderApi
• Add getSerializedNodeId to RecorderApi
• Send telemetry debug for each Core Web Vital

Testing

• Local
• Staging
• Unit
• End to end

---

I have gone over the contributing documentation.

[bcaudan]

LGTM

[codecov-commenter]

Codecov Report

Merging #2344 (8f13844) into main (85dd06b) will decrease coverage by 0.19%.
The diff coverage is 75.43%.

@@            Coverage Diff             @@
##             main    #2344      +/-   ##
==========================================
- Coverage   94.17%   93.99%   -0.19%     
==========================================
  Files         206      208       +2     
  Lines        6134     6175      +41     
  Branches     1358     1368      +10     
==========================================
+ Hits         5777     5804      +27     
- Misses        357      371      +14     

Impacted Files	Coverage Δ
packages/rum-core/src/boot/rumPublicApi.ts	96.47% <ø> (ø)
...ages/rum-core/src/browser/performanceCollection.ts	52.04% <ø> (ø)
.../domain/rumEventsCollection/view/viewCollection.ts	100.00% <ø> (ø)
packages/rum-core/test/noopRecorderApi.ts	60.00% <0.00%> (-15.00%)	⬇️
...entsCollection/view/startWebVitalTelemetryDebug.ts	28.57% <28.57%> (ø)
packages/rum/src/boot/recorderApi.ts	89.09% <66.66%> (-1.30%)	⬇️
...omain/rumEventsCollection/view/trackViewMetrics.ts	96.36% <91.30%> (-1.49%)	⬇️
packages/rum-core/src/boot/startRum.ts	90.00% <100.00%> (+0.20%)	⬆️
...umEventsCollection/view/trackInitialViewTimings.ts	100.00% <100.00%> (ø)
.../src/domain/rumEventsCollection/view/trackViews.ts	100.00% <100.00%> (ø)
... and 1 more

... and 2 files with indirect coverage changes

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