Check for null LOCATION_PROVIDERS_ALLOWED value

After reading LOCATION_PROVIDERS_ALLOWED value from settings provider,
check for null first.

Bug: 72711160
Bug: 72732478
Test: Manual
Change-Id: I813e40f11f078d80c4cc20986f030fdadfe433c6

location/java/android/location/LocationManager.java

@@ -1271,6 +1271,9 @@ public class LocationManager {
         final String allowedProviders = Settings.Secure.getStringForUser(
                 mContext.getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED,
                 userHandle.getIdentifier());
+        if (allowedProviders == null) {
+            return false;
+        }
         final List<String> providerList = Arrays.asList(allowedProviders.split(","));
         for(String provider : getAllProviders()) {
             if (provider.equals(PASSIVE_PROVIDER)) {