MM-11520: Make entity ID checks consistent across api4. (#9395)

* MM-11520: Make entity ID checks consistent across api4.

* Update tests.

api4/user.go

@@ -583,6 +583,12 @@ func updateUser(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// The user being updated in the payload must be the same one as indicated in the URL.
+	if user.Id != c.Params.UserId {
+		c.SetInvalidParam("user_id")
+		return
+	}
+
 	if !c.App.SessionHasPermissionToUser(c.Session, user.Id) {
 		c.SetPermissionError(model.PERMISSION_EDIT_OTHER_USERS)
 		return