Fixes#1297
Ensures proper typing for UUIDs in FastAPI input models, to avoid
explicit conversions, which may throw errors.
This avoids possible 500 errors (due to ValueError exceptions) when
converting UUIDs from user input.
Instead, will get more 422 errors from FastAPI.
UUID conversions remaining are in operator / profile handling where
UUIDs are retrieved from previously set fields, remaining user input
conversions in user auth and collection list are wrapped in exceptions.
For `profileid`, update fastapi models to support union of UUID, null,
and EmptyStr (new empty string only type), to differentiate removing
profile (empty string) vs not changing at all (null) for config updates
4591db1afe