Use request.CTX instead of *request.Context (#24877)

* Use request.CTX instead of *request.Context

* Fix tests

server/channels/app/user_test.go

@@ -698,7 +698,7 @@ func getGitlabUserPayload(gitlabUser oauthgitlab.GitLabUser, t *testing.T) []byt
 	return payload
 }
 
-func createGitlabUser(t *testing.T, a *App, c *request.Context, id int64, username string, email string) (*model.User, oauthgitlab.GitLabUser) {
+func createGitlabUser(t *testing.T, a *App, c request.CTX, id int64, username string, email string) (*model.User, oauthgitlab.GitLabUser) {
 	gitlabUserObj := oauthgitlab.GitLabUser{Id: id, Username: username, Login: "user1", Email: email, Name: "Test User"}
 	gitlabUser := getGitlabUserPayload(gitlabUserObj, t)