fix: disable oauth2 hooks by default

[2ynn]

For new SDKs, both oAuth2ClientCredentialsEnabled and auth.oAuth2PasswordEnabled options are set to true by default even though ClientCredentials and Oauth2Password hooks cannot be used simultaneously.

This PR set both to false by default.

Note: I'd suggest we also add a validation error in case both get set to true at the same time to provide a friendlier error message than:

error calling templateOAuth2PasswordSecurityAccessFunction: Error: Multiple OAuth2 Resource Owner Password fields found at templateOAuth2PasswordSecurityAccessFunction (hooks/hooks.ts:178:11(36))

[bflad]

To be honest, I've always been curious why these are generation configuration flags unlike other generator features which are enabled based on licensing and OAS