[api/lib] instrument validation

[regisoc]

Brief summary of changes

This PR:

• updates the PUT/PATCH instrument endpoints to actually validate the data payload received. The current process is calling the Instrument validate() method, but this method is NOT validating any data. It is only checking the instrument data_entry = complete status, which is counter-intuitive.
• bugfixes the PATCH/PUT instrument flag endpoint. The flag data_entry = 'complete' was checked before the db can be reached to perform the update, which is blocking the update. The current PR should not change the instrument front-end behaviour.

Test instructions

1. bugfix: instrument flag PUT/PATCH blocked on the API not on the front-end.

• Target a candid/visit/instrument with a data_entry = 'complete' flag/state.
• Try updating the Data_entry from the front-end (directly in instrument, accessible by candidate_list > timepoint > instrument) with the right permissions. This should be doable with and without this fix.
• Try the API instrument flag PATCH/PUT endpoint in Swagger API module (i.e. /candidates/{candid}/{visit}/instruments/{instrument}/flags).
• Both endpoint should now accept updates i.e. no 403 error with Can not update instruments that are flagged as complete. message returned.

2. instrument PATCH/PUT endpoint.

• Target a candid/visit/instrument with a data_entry = 'in progress' flag, or update one with the previous 1. endpoint.
• Try the API instrument PATCH/PUT endpoint in Swagger API module (i.e. /candidates/{candid}/{visit}/instruments/{instrument}).
• Both endpoint should now update completely or partly the instrument data.
• Also try with the swagger UI.

Link(s) to related issue(s)

• Resolves [api/lib] instrument endpoints and lib - no data validation #9826

[regisoc]

@kongtiaowang can you make a quick review on this?
I added the PUT/PATCH difference logic + updated the test accordingly.

[kongtiaowang]

@regisoc LGTM

[regisoc]

@driusan assigning you for final review

[regisoc]

@driusan re-asking for final review