Fix baggage parsing for invalid percent-encoded members

[Vcode2407]

Description

Currently, an invalid percent-encoded baggage member can cause parsing of the remaining members in the same baggage header to abort.

For example:

baggage: key1=value1,bad=va%lue,key2=value2

When parsing bad=va%lue, percent decoding throws an IllegalArgumentException, preventing subsequent valid members from being processed.

This change skips only the invalid member and continues processing the remaining members in the header.

A regression test has been added to verify that valid members are preserved when another member contains invalid percent encoding.

Testing

./gradlew :api:all:test --tests io.opentelemetry.api.baggage.propagation.W3CBaggagePropagatorTest

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.53%. Comparing base (a5cd87f) to head (12bf01b).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8480      +/-   ##
============================================
- Coverage     78.54%   78.53%   -0.01%     
- Complexity     8468     8473       +5     
============================================
  Files          1008     1008              
  Lines         28824    28833       +9     
  Branches       3569     3570       +1     
============================================
+ Hits          22639    22644       +5     
- Misses         5342     5343       +1     
- Partials        843      846       +3     

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[psx95]

Thanks for the PR. Was there a related issue reported about this that you came across?
Or was this change motivated by the existing Go and JS implementations?

[psx95]

Could be good to log a warning here.

[Vcode2407]

I looked into this, but left it unchanged since the current parsing behavior appears to favor ignoring invalid baggage and continuing. Happy to update this if logging is preferred.

[psx95]

Isn't the current parsing behavior to throw an exception on invalid baggage?

IMO adding a warning level log about invalid baggage fields makes sense here - that will still let the program continue, but will inform the user that there probably is some invalid encoding in the baggage data.