fix(modal, popover): remove trigger click listeners when overlay is unmounted

[averyjohnston]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
  • Some docs updates need to be made in the ionic-docs repo, in a separate PR. See the contributing guide for details.
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

When ion-modal and ion-popover are disconnected from the DOM, the click listener for opening them via trigger is not removed. Because the listener is on the button etc. rather than the overlay, it isn't garbage collected either.

Issue URL: resolves #26138

What is the new behavior?

For both modal and popover, trigger click listeners are removed and added as the overlay is unmounted and mounted in the DOM.

I added tests for the overlay still being openable after it's been removed and re-added, but there isn't currently a way to check click listeners currently on an element (at least not without monkey-patching addEventListener/removeEventListener beforehand), so I wasn't able to add a test for that part. I manually verified the behavior in the dev tools, though.

Does this introduce a breaking change?

• Yes
• No

Other information