Fix the NPE error when get the service summary.

* Check NPE for AccessibilityInfo.loadSummary()
* Remove the state argument that could get from info argument

Bug: 148837311
Test: Manual test
Change-Id: Ic6906fdbdd7f1c241776d1045be33f89468670b6

src/com/android/settings/accessibility/AccessibilityUtil.java

@@ -98,7 +98,6 @@ final class AccessibilityUtil {
     /** Denotes the accessibility enabled status */
     @Retention(RetentionPolicy.SOURCE)
     public @interface State {
-        int UNKNOWN = -1;
         int OFF = 0;
         int ON = 1;
     }