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>

internal/api/saml/auth_request.go

@@ -3,6 +3,7 @@ package saml
 import (
 	"context"
 	"encoding/base64"
+	"net/http"
 	"net/url"
 
 	"github.com/zitadel/saml/pkg/provider"
@@ -32,9 +33,16 @@ func (p *Provider) CreateResponse(ctx context.Context, authReq models.AuthReques
 		RelayState:      authReq.GetRelayState(),
 		AcsUrl:          authReq.GetAccessConsumerServiceURL(),
 		RequestID:       authReq.GetAuthRequestID(),
-		Issuer:          authReq.GetDestination(),
 		Audience:        authReq.GetIssuer(),
 	}
+
+	issuer := ContextToIssuer(ctx)
+	req, err := http.NewRequestWithContext(provider.ContextWithIssuer(ctx, issuer), http.MethodGet, issuer, nil)
+	if err != nil {
+		return "", "", err
+	}
+	resp.Issuer = p.GetEntityID(req)
+
 	samlResponse, err := p.AuthCallbackResponse(ctx, authReq, resp)
 	if err != nil {
 		return "", "", err