[authn] use authlib client+interceptors for in-proc mode (#93124)

* Add authlib gRPC authenticators for in-proc mode

* implement `StaticRequester` signing in the unified resource client
- [x] when the `claims.AuthInfo` value type is `identity.StaticRequester`, and there's no ID token set, create an internal token and sign it with symmetrical key. This is a workaround for `go-jose` not offering the possibility to create an unsigned token.
- [x] update `IDClaimsWrapper` to support the scenario above
- [x] Switch to using `claims.From()` in `dashboardSqlAccess.SaveDashboard()`

---------

Co-authored-by: gamab <gabriel.mabille@grafana.com>

pkg/tests/apis/helper.go

@@ -33,6 +33,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/accesscontrol/ossaccesscontrol"
 	"github.com/grafana/grafana/pkg/services/accesscontrol/resourcepermissions"
 	"github.com/grafana/grafana/pkg/services/apiserver/endpoints/request"
+	"github.com/grafana/grafana/pkg/services/auth/idtest"
 	"github.com/grafana/grafana/pkg/services/datasources"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/services/org"
@@ -509,6 +510,11 @@ func (c *K8sTestHelper) CreateUser(name string, orgName string, basicRole org.Ro
 	require.Equal(c.t, orgId, s.OrgID)
 	require.Equal(c.t, basicRole, s.OrgRole) // make sure the role was set properly
 
+	idToken, idClaims, err := idtest.CreateInternalToken(s, []byte("secret"))
+	require.NoError(c.t, err)
+	s.IDToken = idToken
+	s.IDTokenClaims = idClaims
+
 	usr := User{
 		Identity: s,
 		password: name,