feat: add custom form json column to sessions, speaker, attendees

[abhinavk96]

Fixes #6434
Fixes #6191

Short description of what this resolves:

Adds fields to accommodate complex custom form values in sessions, speakers and attendees.

[codecov]

Codecov Report

Merging #6435 into development will increase coverage by <.01%.
The diff coverage is 82.35%.

@@               Coverage Diff               @@
##           development    #6435      +/-   ##
===============================================
+ Coverage        64.51%   64.52%   +<.01%     
===============================================
  Files              291      292       +1     
  Lines            15117    15147      +30     
===============================================
+ Hits              9753     9773      +20     
- Misses            5364     5374      +10

Impacted Files	Coverage Δ
app/api/schema/settings.py	100% <100%> (ø)	⬆️
...ts/all/integration/api/validation/test_sessions.py	97.14% <100%> (ø)	⬆️
app/models/speaker.py	94.66% <100%> (+0.14%)	⬆️
app/models/setting.py	91.58% <100%> (+0.08%)	⬆️
app/models/ticket_holder.py	84.31% <100%> (+0.31%)	⬆️
app/models/session.py	90.52% <100%> (+0.2%)	⬆️
app/api/schema/sessions.py	87.34% <100%> (+0.49%)	⬆️
app/api/helpers/validations.py	50% <50%> (ø)
app/api/schema/speakers.py	97.77% <80%> (-2.23%)	⬇️
app/api/schema/attendees.py	98.24% <80%> (-1.76%)	⬇️
... and 2 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update eb8d721...44c80f4. Read the comment docs.

[iamareebjamal]

This will allow users to add arbritrarily nested JSON to the DB. Please add validation for only flat JSON

[abhinavk96]

@iamareebjamal Added a validation check to only allow flattened JSON. Verified locally by passing a two-level deep JSON object.

[iamareebjamal]

{
  "a": [{... big nested data ...}, {... big nested data ...}, {... big nested data ...}] 
}

This will be supported

[iamareebjamal]

Also, let's add a limit to the fields in settings. By default, allow only 30 items. I think it is fair. If more are required, then it can be changed by the admin

[abhinavk96]

{
  "a": [{... big nested data ...}, {... big nested data ...}, {... big nested data ...}] 
}

This will be supported

@iamareebjamal for this can we impose that the value has to be a string or number or null, that will eliminate the possibility of a list or other unsupported types.

[iamareebjamal]

Agree. string, number, null, or boolean

[abhinavk96]

@iamareebjamal Please take a look now.