Fix enter key support for generic dialog box

[steverep]

Proposed change

Fix enter key support for generic dialog box by removing unnecessary handlers as described in my comment and review of #12360. The mwc-dialog component handles the key press, so all this dialog has to do is grab the current value.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example configuration

Additional information

• This PR fixes or closes issue: fixes Pushing the "Enter" key on the Password Change modal closes the modal #12206
• This PR is related to issue or discussion:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.