pydantic updates: deprecating sane_defaults, nested properties, httpurl, is_user_url

[devxpy]

You can now specify request model defaults as pydantic field defaults (these will take precedence over sane_defaults now)

ref: e733599 (#341)

E.g.

You can also do nested keys in the api now (better dev UX). Only catch is that you can't then use key for components, and must use value instead (e.g settings.still = st.checkbox(..., value=settings.still) )

For any fields that are URLs, please set the type to FieldHttpUrl for better validation error messages in the API

When downloading user URLs, use is_user_url=True

This will give better error messages and sort our sentry logs which are filled with request errors