Improve Subjects searchbar UI

[helen-m-lin]

Is your feature request related to a problem? Please describe.
We added a new UI for aind-metadata-service with searchbars for the Subject endpoint to start. @sharmishtaa had a few suggestions to improve the UI.

Describe the solution you'd like

1. Make endpoint label in title less confusing. Currently it shows as /subject/{subject_id} and looks like it may be selectable. Change it to explicitly show that is the endpoint, or remove it.
2. Allow users to submit by pressing enter.
3. Put Data before Message (so that validation errors are shown after the actual data json)
4. Consider not highlighting certain error responses in red (e.g. if there is data but returns 406 because of validation errors)

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
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