Fix flaky of FileManagementUiTest

FileManagementUiTest sometimes fails due to the target UI object to
be clicked is not ready after item selection. This CL ensures to wait
until the item selection is completed.

Bug: 121338354
Test: atest DocumentsUITests
Change-Id: Id687089bf426639faf3c67668c223d42a80af42e
diff --git a/tests/functional/com/android/documentsui/FileManagementUiTest.java b/tests/functional/com/android/documentsui/FileManagementUiTest.java
index 5157ec3..58be747 100644
--- a/tests/functional/com/android/documentsui/FileManagementUiTest.java
+++ b/tests/functional/com/android/documentsui/FileManagementUiTest.java
@@ -77,7 +77,7 @@
     }
 
     public void testDeleteDocument() throws Exception {
-        bots.directory.selectDocument("file1.png");
+        bots.directory.selectDocument("file1.png", 1);
         device.waitForIdle();
         bots.main.clickToolbarItem(R.id.action_menu_delete);
 
@@ -88,7 +88,7 @@
     }
 
     public void testKeyboard_CutDocument() throws Exception {
-        bots.directory.selectDocument("file1.png");
+        bots.directory.selectDocument("file1.png", 1);
         device.waitForIdle();
         bots.keyboard.pressKey(KeyEvent.KEYCODE_X, KeyEvent.META_CTRL_ON);
 
@@ -105,7 +105,7 @@
     }
 
     public void testKeyboard_CopyDocument() throws Exception {
-        bots.directory.selectDocument("file1.png");
+        bots.directory.selectDocument("file1.png", 1);
         device.waitForIdle();
         bots.keyboard.pressKey(KeyEvent.KEYCODE_C, KeyEvent.META_CTRL_ON);
 
@@ -121,7 +121,7 @@
     }
 
     public void testDeleteDocument_Cancel() throws Exception {
-        bots.directory.selectDocument("file1.png");
+        bots.directory.selectDocument("file1.png", 1);
         device.waitForIdle();
         bots.main.clickToolbarItem(R.id.action_menu_delete);