feat: actions v2 for functions (#9420)

# Which Problems Are Solved

Actions v2 are not executed in different functions, as provided by the
actions v1.

# How the Problems Are Solved

Add functionality to call actions v2 through OIDC and SAML logic to
complement tokens and SAMLResponses.

# Additional Changes

- Corrected testing for retrieved intent information
- Added testing for IDP types
- Corrected handling of context for issuer in SAML logic

# Additional Context

- Closes #7247 
- Dependent on https://github.com/zitadel/saml/pull/97
- docs for migration are done in separate issue:
https://github.com/zitadel/zitadel/issues/9456

---------

Co-authored-by: Silvan <27845747+adlerhurst@users.noreply.github.com>

proto/zitadel/user/v2/user_service.proto

@@ -2094,6 +2094,7 @@ message RetrieveIdentityProviderIntentResponse{
       example: "\"163840776835432345\"";
     }
   ];
+  AddHumanUserRequest add_human_user = 4;
 }
 
 message AddIDPLinkRequest{