core: Avoid DeadSystemException recursion when dropbox is unavailable

During early boot, framework callers can ask for DropBoxManager before the
`dropbox` binder has been published. Using getServiceOrThrow() sends that path
through onServiceNotFound(), which emits another WTF from a core process and can
cascade into recursive error handling while system_server is already failing.

Switch DROPBOX_SERVICE to ServiceManager.getService(), return null while the
binder is still absent, and treat dropbox as an allowed transiently-unavailable
service in getSystemService(). This keeps the early-boot path null-safe without
spamming an extra WTF that can amplify DeadSystemException-style failures.

Signed-off-by: Quince <quinceroms@gmail.com>

Author: QuinceROMs

core/java/android/app/SystemServiceRegistry.java

@@ -580,7 +580,10 @@ public BatteryManager createService(ContextImpl ctx) throws ServiceNotFoundExcep
                 new CachedServiceFetcher<DropBoxManager>() {
             @Override
             public DropBoxManager createService(ContextImpl ctx) throws ServiceNotFoundException {
-                IBinder b = ServiceManager.getServiceOrThrow(Context.DROPBOX_SERVICE);
+                IBinder b = ServiceManager.getService(Context.DROPBOX_SERVICE);
+                if (b == null) {
+                    return null;
+                }
                 IDropBoxManagerService service = IDropBoxManagerService.Stub.asInterface(b);
                 return new DropBoxManager(ctx, service);
             }});
@@ -2109,6 +2112,7 @@ public static Object getSystemService(@NonNull ContextImpl ctx, String name) {
                 case Context.CONTEXTHUB_SERVICE:
                 case Context.VIRTUALIZATION_SERVICE:
                 case Context.VIRTUAL_DEVICE_SERVICE:
+                case Context.DROPBOX_SERVICE:
                     return null;
                 case Context.VCN_MANAGEMENT_SERVICE:
                     if (!hasSystemFeatureOpportunistic(ctx,