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

* Use request.CTX instead of *request.Context

* Fix tests

server/channels/app/platform/helper_test.go

@@ -21,7 +21,7 @@ import (
 )
 
 type TestHelper struct {
-	Context *request.Context
+	Context request.CTX
 	Service *PlatformService
 	Suite   SuiteIFace