fix: re-sync SSH deploy keys when updating site source control

[urufudev]

When a user updates the Source Control provider/token for an existing site (via Settings → Source Controls), the SSH deploy key is not automatically re-registered in the repository. This leads to Permission denied (publickey) errors during subsequent deployments.

This PR updates UpdateSourceControl.php to:

1. Remove the old deploy key from the previous source control provider (if it exists).
2. Register the existing SSH key with the new source control provider/token.
3. Store the new deploy_key_id in type_data to ensure DeleteSite can correctly clean it up later.

Changes:
Modified app/Actions/Site/UpdateSourceControl.php to include the logic for deleting the old key and creating the new one using the existing Site and SourceControl providers.

Verification:

1. Tested on local and production (DigitalOcean) servers.
2. Verified that keys are correctly created in GitHub with the expected {domain}-key-{id} format.
3. Verified that the previous key is removed before creating the new one to avoid clutter.

[saeedvaziry]

@urufudev thanks for the PR. I'd appreceate test coverage for this