Translate dashboard panel url error message

[steinmn]

Proposed change

If the user tries to create a new dashboard with a URL that already exist, the current error message contains technical details and is not translatable (#27162).

This PR uses the translation_key from the updated error message in home-assistant/core#153501 to display an improved translated error message.

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 Dashboard panel URL error message contains technical details #27162
• 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.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io