[Panlingual] Improve performance of displaying app list in Settings.

- Use existed ApplicationInfo to get needed info.
 - Add unittest to AppLocaleUtil.java

Bug: b/238054165
Bug: b/231904717
Test: Maunal test passed
Test: atest passed
Change-Id: I23f354c366b45d4b684184b3366aeab913bcd3c8

tests/spa_unit/src/com/android/settings/spa/app/appinfo/AppLocalePreferenceTest.kt

@@ -77,7 +77,8 @@ class AppLocalePreferenceTest {
             .strictness(Strictness.LENIENT)
             .startMocking()
         whenever(context.packageManager).thenReturn(packageManager)
-        whenever(AppLocaleUtil.canDisplayLocaleUi(any(), eq(PACKAGE_NAME), any())).thenReturn(true)
+        whenever(AppLocaleUtil.canDisplayLocaleUi(any(), ArgumentMatchers.eq(APP), any()))
+                .thenReturn(true)
         whenever(AppLocaleDetails.getSummary(any(), ArgumentMatchers.eq(APP))).thenReturn(SUMMARY)
     }
 
@@ -88,7 +89,8 @@ class AppLocalePreferenceTest {
 
     @Test
     fun whenCanNotDisplayLocalUi_notDisplayed() {
-        whenever(AppLocaleUtil.canDisplayLocaleUi(any(), eq(PACKAGE_NAME), any())).thenReturn(false)
+        whenever(AppLocaleUtil.canDisplayLocaleUi(any(), ArgumentMatchers.eq(APP), any()))
+                .thenReturn(false)
 
         setContent()