Add missing conn-fields for providers migrated to yaml

[amoghrajesh]

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Was generative AI tooling used to co-author this PR?

• Yes - cursor IDE

After #62011 was merged, realised a few things that were missed:

• conn-fields and ui-field-behaviour both need to be added to provider.yaml for each connection type
• The migration script needed to be fixed to generate nullable types (["string", "null"]) matching legacy behavior per jsonschema where all extra fields are optional OR UI was rendering all fields as required

Things render fine now:

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[github-actions]

Backport failed to create: v3-1-test. View the failure log Run details

Note: As of Merging PRs targeted for Airflow 3.X
the committer who merges the PR is responsible for backporting the PRs that are bug fixes (generally speaking) to the maintenance branches.

In matter of doubt please ask in #release-management Slack channel.

Status	Branch	Result
❌	v3-1-test

You can attempt to backport this manually by running:

cherry_picker 4404bc0 v3-1-test

This should apply the commit to the v3-1-test branch and leave the commit in conflict state marking
the files that need manual conflict resolution.

After you have resolved the conflicts, you can continue the backport process by running:

cherry_picker --continue

If you don't have cherry-picker installed, see the installation guide.

[amoghrajesh]

Ah no need to backport this