Rebuild profiling request for every profiling start

[ambushwork]

What does this PR do?

Prior to this PR, in PerfettoProfile the cancel signal and profiling request are created only when the class is initialized (not recreated if the start is called for another time), which causes the following request can't be cancelled, because the original cancel signal is already cancelled before thus in a "cancelled" state.

Motivation

This changes will be necessary to support multiple profiling request in the future.

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)

[datadog-official]

🎯 Code Coverage
• Patch Coverage: 93.75%
• Overall Coverage: 66.42% (+0.02%)

View detailed report

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: b9ae78a | Docs | Datadog PR Page | Was this helpful? Give us feedback!}

[codecov-commenter]

Codecov Report

❌ Patch coverage is 92.30769% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 71.33%. Comparing base (4f0483e) to head (b9ae78a).
⚠️ Report is 2 commits behind head on feature/perfetto-profiling.

Files with missing lines	Patch %	Lines
...id/profiling/internal/perfetto/PerfettoProfiler.kt	92.31%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@                      Coverage Diff                       @@
##           feature/perfetto-profiling    #3076      +/-   ##
==============================================================
+ Coverage                       71.28%   71.33%   +0.05%     
==============================================================
  Files                             893      893              
  Lines                           32689    32694       +5     
  Branches                         5493     5495       +2     
==============================================================
+ Hits                            23302    23321      +19     
+ Misses                           7827     7817      -10     
+ Partials                         1560     1556       -4     

Files with missing lines	Coverage Δ
...id/profiling/internal/perfetto/PerfettoProfiler.kt	92.06% <92.31%> (-2.76%)	⬇️

... and 38 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.