[Plugin User Interaction]: Improve causality of spans from bubbled events

[johnbley]

Which problem is this PR solving?

• Currently when bubbled events trigger multiple listeners, we create separate spans/traces for each of them, even though they were causally related. It also makes it hard to see whether multiple "clicks" happened or just one.

Short description of the changes

• Track event bubbling and assign parent span relationship (lowest traced handler on event bubble gets top-most span, other higher-element handlers are tracked as child spans recursively).

[codecov]

Codecov Report

Merging #172 into master will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #172   +/-   ##
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  Coverage   94.30%   94.31%           
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  Files          77       77           
  Lines        3830     3836    +6     
  Branches      413      415    +2     
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+ Hits         3612     3618    +6     
  Misses        218      218           

Impacted Files	Coverage Δ
...try-plugin-user-interaction/src/userInteraction.ts	93.95% <0.00%> (+0.14%)	⬆️

[dyladan]

Seems fine to me by I'm not an expert on this plugin. Would like to get @obecny feedback.

[obecny]

overall lgtm, I just would like to ask you to update the image images/main-sync.jpg to show how the trace will look like now after this change.

[johnbley]

overall lgtm, I just would like to ask you to update the image images/main-sync.jpg to show how the trace will look like now after this change.

There's no difference in the examples because of this change - this only affects scenarios where event listeners on bubbling events are added at multiple levels of the DOM tree, which the examples don't do.