fix(modal): role attribute can be customized

[liamdebeasi]

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?

Issue URL: N/A

During our discussions about #23108 I realized that the role attribute could not be customized. Long term I think it would be best to move these attribute details to .modal-wrapper since that is where the actual modal content is, but that requires some broader focus trapping fixes first. As a result, I propose we move role="dialog" to the host for now and make it customizable.

Without this fix, it will not be possible to use the Custom Dialogs feature in an accessible way (for example: setting role to alertdialog)

What is the new behavior?

• Role can now be customized

Does this introduce a breaking change?

• Yes
• No

Other information