Move hide action logic after `showchange` event

If not waiting for `showchange`, the underneath API element may not fully initialized
and will throw error when try to setActionHidden.

Change-Id: Iaa664f5ed29e56504dd30789c42ab12a4ddcb4db

src/main/resources/static/find-owners.js

diff --git a/src/main/resources/static/find-owners.js b/src/main/resources/static/find-owners.js
index f47ebad..dce2ead 100644
--- a/src/main/resources/static/find-owners.js
+++ b/src/main/resources/static/find-owners.js
@@ -17,8 +17,11 @@
   if (ENABLED_EXPERIMENTS.includes('UiFeature__plugin_code_owners')) {
     // Disable if experiment UiFeature__plugin_code_owners is enabled
     // Also hide previous 'Find Owners' button under 'MORE'.
-    var changeActions = self.changeActions();
-    changeActions.setActionHidden('revision', 'find-owners~find-owners', true);
+    function removeFindOwnerFromSecondaryActions() {
+      var changeActions = self.changeActions();
+      changeActions.setActionHidden('revision', 'find-owners~find-owners', true);
+    }
+    self.on('showchange', removeFindOwnerFromSecondaryActions);
     return;
   }