UI - Connection Form issue when submitting a string for extra json.

[pierrejeambrun]

Body

As mentioned in #53943 (review)

If we try to save a connection with a string for the 'Extra field json' API is returning an error 500. (picture 1)

There is two issue with that, first of all the UI should not allow this to be submitted, similarly to malformed json (picture 2)

Also the backend shouldn't crash if the extra is an unstructured string. (That's because of the action_login function expecting only parsable json as extra which isn't correct).

Committer

• I acknowledge that I am a maintainer/committer of the Apache Airflow project.

[pierrejeambrun]

Tagging for 3.0.5 as I suspect this was bugged since 3.0.0 and there are other critical bug fixes to fix for 3.0.4

[Prasanth345]

@pierrejeambrun, i would like to work on this