feat(opentelemetry-web): capture decodedBodySize / http.response_content_length_uncompressed

[t2t2]

Add capturing decodedBodySize from resource timings. As per spec it should be only included if content encoding (eg. gzip, brotli) is being used (in which case encoded and decoded sizes are different)

Past related: #1262 (comment)

[codecov]

Codecov Report

Merging #2343 (ef19dc3) into main (2355717) will increase coverage by 0.54%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #2343      +/-   ##
==========================================
+ Coverage   92.36%   92.91%   +0.54%     
==========================================
  Files         128      143      +15     
  Lines        4243     5135     +892     
  Branches      866     1051     +185     
==========================================
+ Hits         3919     4771     +852     
- Misses        324      364      +40     

Impacted Files	Coverage Δ
packages/opentelemetry-web/src/types.ts	100.00% <ø> (ø)
...ntelemetry-web/src/enums/PerformanceTimingNames.ts	100.00% <100.00%> (ø)
packages/opentelemetry-web/src/utils.ts	94.90% <100.00%> (ø)
...emetry-instrumentation-xml-http-request/src/xhr.ts	97.58% <0.00%> (ø)
...mentation-xml-http-request/src/enums/EventNames.ts	100.00% <0.00%> (ø)
...kages/opentelemetry-exporter-collector/src/util.ts	100.00% <0.00%> (ø)
...ation-xml-http-request/src/enums/AttributeNames.ts	100.00% <0.00%> (ø)
...kages/opentelemetry-web/src/StackContextManager.ts	94.28% <0.00%> (ø)
...ry-exporter-collector/src/CollectorExporterBase.ts	92.15% <0.00%> (ø)
... and 8 more

[johnbley]

LGTM