Add propagation to filtered out events from HttpClient

[utpilla]

Fixes #1561 Item#2

Changes

• Moved the filtering logic to HttpHandlerDiagnosticListener.cs OnStartActivity method from HttpClientInstrumentation.cs
• Updated logic of OnStartActivity to inject propagation data into Headers for filtered out events as well

[codecov]

Codecov Report

Merging #1707 (8ba3aa2) into master (9e9987a) will decrease coverage by 0.01%.
The diff coverage is 73.33%.

@@            Coverage Diff             @@
##           master    #1707      +/-   ##
==========================================
- Coverage   82.15%   82.13%   -0.02%     
==========================================
  Files         250      250              
  Lines        6763     6774      +11     
==========================================
+ Hits         5556     5564       +8     
- Misses       1207     1210       +3     

Impacted Files	Coverage Δ
...tp/Implementation/HttpHandlerDiagnosticListener.cs	71.11% <66.66%> (-1.73%)	⬇️
....Instrumentation.Http/HttpClientInstrumentation.cs	100.00% <100.00%> (ø)
...p/Implementation/HttpInstrumentationEventSource.cs	64.00% <100.00%> (+3.13%)	⬆️
...Telemetry/Internal/SelfDiagnosticsEventListener.cs	94.28% <0.00%> (+1.42%)	⬆️

[CodeBlanch]

LGTM

[utpilla]

Closing and re-opening this PR to trigger a Build Run.