Revert "Fix the accessibility shortcut funtionaility."

This reverts commit 72c52dfb48.

Reason for revert: The original commit only changed what was displayed in the settings, but not the actual value of the setting that was used during the shortcut operation.

Bug: b/269693551
Test: Locally tested on adt4-userdebug that the shortcut does not show TalkBack as target service if it is set to an empty string and the settings are opened for the very first time.

Change-Id: Ife2e098d1e55ed94efb2426505872546b27bc3bb
(cherry picked from commit db7d6590a3)
Merged-In: Ife2e098d1e55ed94efb2426505872546b27bc3bb

packages/SettingsLib/src/com/android/settingslib/accessibility/AccessibilityUtils.java

@@ -183,7 +183,7 @@ public class AccessibilityUtils {
         final String currentShortcutServiceId = Settings.Secure.getStringForUser(
                 context.getContentResolver(), Settings.Secure.ACCESSIBILITY_SHORTCUT_TARGET_SERVICE,
                 userId);
-        if (!TextUtils.isEmpty(currentShortcutServiceId)) {
+        if (currentShortcutServiceId != null) {
             return currentShortcutServiceId;
         }
         return context.getString(R.string.config_defaultAccessibilityService);