Authn: Sync authlib and update how we construct authn client interceptor (#101124)

* Sync authlib and update how we construct authn client interceptor

* Remove namespace from checker

pkg/services/authn/grpcutils/inproc_exchanger.go

@@ -1,10 +1,8 @@
 package grpcutils
 
 import (
-	"context"
 	"encoding/base64"
 	"encoding/json"
-	"fmt"
 
 	"github.com/go-jose/go-jose/v3/jwt"
 	"github.com/grafana/authlib/authn"
@@ -12,29 +10,21 @@ import (
 	"github.com/grafana/grafana/pkg/apimachinery/identity"
 )
 
-type inProcExchanger struct {
-	tokenResponse *authn.TokenExchangeResponse
-}
-
-func ProvideInProcExchanger() *inProcExchanger {
-	tokenResponse, err := createInProcToken()
+func ProvideInProcExchanger() authn.StaticTokenExchanger {
+	token, err := createInProcToken()
 	if err != nil {
 		panic(err)
 	}
 
-	return &inProcExchanger{tokenResponse}
+	return authn.NewStaticTokenExchanger(token)
 }
 
-func (e *inProcExchanger) Exchange(ctx context.Context, r authn.TokenExchangeRequest) (*authn.TokenExchangeResponse, error) {
-	return e.tokenResponse, nil
-}
-
-func createInProcToken() (*authn.TokenExchangeResponse, error) {
+func createInProcToken() (string, error) {
 	claims := authn.Claims[authn.AccessTokenClaims]{
 		Claims: jwt.Claims{
-			Audience: []string{"resourceStore"},
 			Issuer:   "grafana",
 			Subject:  types.NewTypeID(types.TypeAccessPolicy, "grafana"),
+			Audience: []string{"resourceStore"},
 		},
 		Rest: authn.AccessTokenClaims{
 			Namespace:            "*",
@@ -48,15 +38,13 @@ func createInProcToken() (*authn.TokenExchangeResponse, error) {
 		"typ": authn.TokenTypeAccess,
 	})
 	if err != nil {
-		return nil, err
+		return "", err
 	}
 
 	payload, err := json.Marshal(claims)
 	if err != nil {
-		return nil, err
+		return "", err
 	}
 
-	return &authn.TokenExchangeResponse{
-		Token: fmt.Sprintf("%s.%s.", base64.RawURLEncoding.EncodeToString(header), base64.RawURLEncoding.EncodeToString(payload)),
-	}, nil
+	return base64.RawURLEncoding.EncodeToString(header) + "." + base64.RawURLEncoding.EncodeToString(payload) + ".", nil
 }