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

* Use request.CTX instead of *request.Context

* Fix tests

server/channels/store/sqlstore/integrity_test.go

@@ -317,7 +317,7 @@ func createScheme(ss store.Store) *model.Scheme {
 	return s
 }
 
-func createSession(c *request.Context, ss store.Store, userId string) *model.Session {
+func createSession(c request.CTX, ss store.Store, userId string) *model.Session {
 	m := model.Session{}
 	m.UserId = userId
 	s, _ := ss.Session().Save(c, &m)