Improvements in providers

[SaadBazaz]

• Change key for chrome built-in AI: It should probably be chrome-built-in-ai instead of just chrome
• Maybe add a callback or hook for the custom provider, so they have full control on how the request is sent
• Allow each Form to have these providers / options overridden (ideally, the Provider and the Form should share the same props, meaning EVERYTHING should be overridable on the Form level)