Fix editor_doc_cache locked on editor startup

(cherry picked from commit e064efccbc0c48576bc23087ba8fd0773d13714d)

platform/android/export/export_plugin.cpp

@@ -290,7 +290,9 @@ void EditorExportPlatformAndroid::_check_for_changes_poll_thread(void *ud) {
 
 		// Check for devices updates
 		String adb = get_adb_path();
-		if (ea->has_runnable_preset.is_set() && FileAccess::exists(adb)) {
+		// adb.exe was locking the editor_doc_cache file on startup. Adding a check for is_editor_ready provides just enough time
+		// to regenerate the doc cache.
+		if (ea->has_runnable_preset.is_set() && FileAccess::exists(adb) && EditorNode::get_singleton()->is_editor_ready()) {
 			String devices;
 			List<String> args;
 			args.push_back("devices");