Add email validation in user settings

[chuckbutkus]

This PR adds email validation to the user settings page:

• Added client-side email validation using regex pattern
• Added visual feedback for invalid email formats
• Disabled the save button when the email format is invalid
• Added translations for the validation error message

These changes improve the user experience by providing immediate feedback on email format validity and prevent submission of invalid email addresses.

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To run this PR locally, use the following command:

docker run -it --rm   -p 3000:3000   -v /var/run/docker.sock:/var/run/docker.sock   --add-host host.docker.internal:host-gateway   -e SANDBOX_RUNTIME_CONTAINER_IMAGE=docker.all-hands.dev/all-hands-ai/runtime:539d620-nikolaik   --name openhands-app-539d620   docker.all-hands.dev/all-hands-ai/openhands:539d620

[openhands-ai]

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@OpenHands please fix the failing actions on PR #8952

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[github-actions]

This PR is stale because it has been open for 30 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[github-actions]

This PR was closed because it has been stalled for over 30 days with no activity.