Fix invalid timings in span events

[Abinet18]

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Which problem is this PR solving?

Fix invalid timings in span events

Fixes # (issue)

https://github.com/open-telemetry/opentelemetry-js/issues/4478

Short description of the changes

add reference time to check if the value to be reported for the event is sane (use max of time and reference time)

Type of change

Please delete options that are not relevant.

• [ ] Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Checklist:

• [ ] Followed the style guidelines of this project
• [ ] Unit tests have been added
• [ ] Documentation has been updated

[codecov[bot]]

Codecov Report

Merging #4486 (98c1496) into main (5231aa2) will increase coverage by 0.01%. The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4486      +/-   ##
==========================================
+ Coverage   92.80%   92.82%   +0.01%     
==========================================
  Files         328      328              
  Lines        9512     9519       +7     
  Branches     2047     2050       +3     
==========================================
+ Hits         8828     8836       +8     
+ Misses        684      683       -1     

Files	Coverage Δ
packages/opentelemetry-sdk-trace-web/src/utils.ts	93.92% <100.00%> (+0.24%)	:arrow_up:

... and 1 file with indirect coverage changes

[Abinet18]

@MSNev , @martinkuba , @dyladan , can you review this ?