feat: add default none to pydantic validators

[rzlim08]

• Creates a default None value for the pydantic validators
• Allows the pydantic validators to be used directly

[jgadling]

Do you mind explaining why the default None makes the validators easier to use? @rzlim08

[rzlim08]

Do you mind explaining why the default None makes the validators easier to use? @rzlim08

Yep, since we're using the validators directly, this allows for the case where you don't want to set all of the optional variables, for example for Update events only having to set the variable that you want to change. I think we didn't have to do this before because we were combining the validators with the Strawberry Types which already have defaults.