ash: drop dep on SelectFile params

This change refactors VmApplicationsServiceProvider. Previously:

* SelectFileData owned a DialogListener
* SelectFileData owned a FileSelectedSignal
* Ownership of SelectFileData was passed to DialogListener's FileSelected()
  callback
* DialogListener passed the SelectFileData (which owned the DialogListener
  itself) to ShareWithVMAndTranslateToFileUrls() as a bound callback arg
* ShareWithVMAndTranslateToFileUrls() did a bunch of asynchronous Stuff and
  ultimately ran the callback
* The bound callback accessed the signal field out of the passed SelectFileData
  and then dropped ownership of it

After this change:
* SelectFileData does not exist
* DialogListener owns itself and a FileSelectedSignal
* DialogListener self-deletes in its FileSelected() callback and passes only its
  signal field to the bound callback

This simplifies the ownership relationship (imo) and also drops the dependency
on the deprecated `params` mechanism in SelectFile().

Bug: 340178601
Change-Id: I95423822dcf5603ed221903b9d02270ad16b7511
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5685318
Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Auto-Submit: Elly FJ <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1325166}