Add example using addProtocol to transform vector tile feature properties

[neodescis]

Provides an example of how to solve #4198 using addProtocol.

IMO, this should be favored over #5343 and #4199.

Launch Checklist

• Confirm your changes do not include backports from Mapbox projects (unless with compliant license) - if you are not sure about this, please ask!
• Briefly describe the changes in this PR.
• Link to related issues.
• Include before/after visuals or gifs if this PR includes visual changes.
• Write tests for all new functionality.
• Document any changes to public APIs.
• Post benchmark scores.
• Add an entry to CHANGELOG.md under the ## main section.

[neodescis]

@wipfli, check this out. This is how I solved the problem using addProtocol. I believe this is cleaner than our other approach. I'm curious to hear what you think!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.95%. Comparing base (f1d58f2) to head (8e92646).
Report is 22 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5370      +/-   ##
==========================================
+ Coverage   91.84%   91.95%   +0.10%     
==========================================
  Files         282      282              
  Lines       38908    38908              
  Branches     6827     6820       -7     
==========================================
+ Hits        35735    35777      +42     
+ Misses       3046     3003      -43     
- Partials      127      128       +1     

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[HarelM]

Shouldn't this return something in "regular" cases?

[neodescis]

If a request transform doesn't return, or returns undefined/null, then nothing happens and the original request parameters are used. I can add the return undefined to be clear though.

[HarelM]

This is a very nice examples!

[HarelM]

It would be interesting to see how this example can be done in a worker thread instead of the main thread, but this is a "nice to have".
In any case, I think the other two PRs can be closed, this is a good enough way to solve this I think...

[wipfli]

Amazing, thanks for writing this example @neodescis. It great to see how this works with add protocol, and also it is interesting to have now an example which uses import in the html. I always wondered how to do this...