[WNMGDS-2521] Add custom event handling to web components

[zarahzachz]

WNMGDS-2521

• Skipping analytics unit tests until solution can be agreed upon
  • Web component define function overwrites default analytics function; need to figure out how to fix this
  • Alert analytics fire before events can be added
• Update USA banner web component snapshot (changes due to Learn's whitespace solution)
• Add functionality to define custom events on a web component

[pwolfert]

Just had an idea that we could explore later: What if instead of trying to define the callback that they add as one of the props (which clobbers any listeners we made before) we instead added an event listener in this function? Like bob.onChange = myCallback results in bob.addEventListener('ds-change', myCallback)?

[pwolfert]

We could pull the kebabCaseIt(name.replace('on', 'ds')) logic out into its own function and then use it here in this set function and in the proxyEvents function

[pwolfert]

Since this is mostly about adding the event-handling code, could the PR title reflect that?

[pwolfert]

Good work! This is an exciting feature

[pwolfert]

Do you know why this changed? I don't see code that actually defines the root-id, but I also don't see that it was removed in this branch. Like I get why the static id isn't present, but why was it ever static before?

[zarahzachz]

i noticed the static id wasn't set and figured this was a fix but no clue why it changed.