[quickview] Assert that the test remote fakeMouseClick worked

Addresses post-facto review comments of CL:2026548.

Bug: 1038799
Change-Id: Id22e54a6824d7d28028145f5ef5eef3efb8ff846
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2029560
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736785}

ui/file_manager/integration_tests/file_manager/quick_view.js

@@ -234,8 +234,8 @@
     // Click the file-list context menu "Get info" command.
     const getInfoMenuItem = '#file-context-menu:not([hidden]) ' +
         ' [command="#get-info"]:not([hidden])';
-    await remoteCall.callRemoteTestUtil(
-        'fakeMouseClick', appId, [getInfoMenuItem]);
+    chrome.test.assertTrue(!!await remoteCall.callRemoteTestUtil(
+        'fakeMouseClick', appId, [getInfoMenuItem]));
 
     // Check: the Quick View dialog should be shown.
     const caller = getCaller();
@@ -276,8 +276,8 @@
     // Click the file-list context menu "Get info" command.
     const getInfoMenuItem = '#file-context-menu:not([hidden]) ' +
         ' [command="#get-info"]:not([hidden])';
-    await remoteCall.callRemoteTestUtil(
-        'fakeMouseClick', appId, [getInfoMenuItem]);
+    chrome.test.assertTrue(!!await remoteCall.callRemoteTestUtil(
+        'fakeMouseClick', appId, [getInfoMenuItem]));
 
     // Check: the Quick View dialog should be shown.
     const caller = getCaller();