merge_pr_50159

Get started cleaning up interesttarget implementation [1/N]

This is the first in a series of patches to clean up and update the
interesttarget implementation to match recent OpenUI discussions.

This CL:

• Gets rid of interestaction. See the large comment posted here:
  openui/open-ui#1064 (comment)
• Adds a connection to InterestLost when elements are de-focused.
• Adds support (tentatively) for dialogs being shown modally.
• Remove keyboard/focus support for interesttarget. This will
  get re-added later in its new form, via a hotkey rather than
  focus.

Bug: 326681249
Change-Id: I26f07a00c4fb1d2b1da92b64d91f330c02a11468
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6166890
Auto-Submit: Mason Freed [email protected]
Reviewed-by: David Baron [email protected]
Commit-Queue: Mason Freed [email protected]
Cr-Commit-Position: refs/heads/main@{#1408202}