MM-57245: Bump up Go version to 1.21 (#26512)

* MM-57245: Bump up Go version to 1.21

https://mattermost.atlassian.net/browse/MM-57245
```release-note
NONE
```

server/cmd/mmctl/commands/permissions_e2e_test.go

@@ -39,7 +39,7 @@ func (s *MmctlE2ETestSuite) TestShowRoleCmd() {
 func (s *MmctlE2ETestSuite) TestAddPermissionsCmd() {
 	s.SetupEnterpriseTestHelper().InitBasic()
 
-	role, appErr := s.th.App.GetRoleByName(context.Background(), model.SystemUserRoleId)
+	role, appErr := s.th.App.GetRoleByName(context.TODO(), model.SystemUserRoleId)
 	s.Require().Nil(appErr)
 	s.Require().NotContains(role.Permissions, model.PermissionCreateBot.Id)
 
@@ -66,7 +66,7 @@ func (s *MmctlE2ETestSuite) TestAddPermissionsCmd() {
 
 		s.Require().Len(printer.GetLines(), 0)
 		s.Require().Len(printer.GetErrorLines(), 0)
-		updatedRole, appErr := s.th.App.GetRoleByName(context.Background(), model.SystemUserRoleId)
+		updatedRole, appErr := s.th.App.GetRoleByName(context.TODO(), model.SystemUserRoleId)
 		s.Require().Nil(appErr)
 		s.Require().Contains(updatedRole.Permissions, model.PermissionCreateBot.Id)
 	})
@@ -75,7 +75,7 @@ func (s *MmctlE2ETestSuite) TestAddPermissionsCmd() {
 func (s *MmctlE2ETestSuite) TestRemovePermissionsCmd() {
 	s.SetupEnterpriseTestHelper().InitBasic()
 
-	role, appErr := s.th.App.GetRoleByName(context.Background(), model.SystemUserRoleId)
+	role, appErr := s.th.App.GetRoleByName(context.TODO(), model.SystemUserRoleId)
 	s.Require().Nil(appErr)
 	s.Require().Contains(role.Permissions, model.PermissionCreateDirectChannel.Id)
 
@@ -103,7 +103,7 @@ func (s *MmctlE2ETestSuite) TestRemovePermissionsCmd() {
 		s.Require().Len(printer.GetLines(), 0)
 		s.Require().Len(printer.GetErrorLines(), 0)
 
-		updatedRole, appErr := s.th.App.GetRoleByName(context.Background(), model.SystemUserRoleId)
+		updatedRole, appErr := s.th.App.GetRoleByName(context.TODO(), model.SystemUserRoleId)
 		s.Require().Nil(appErr)
 		s.Require().NotContains(updatedRole.Permissions, model.PermissionCreateDirectChannel.Id)
 	})