Enable static RROs by default

Static RROs should be always enabled.
This is a missing part from ag/1949458.
The design details are in go/treble-static-rro.

Test: building succeeded and tested with static RROs.
Bug: 35742444
Change-Id: Ia9851f91c97cdde2436a29a161194eeb56ea47d5

services/core/java/com/android/server/om/OverlayManagerServiceImpl.java

@@ -102,7 +102,8 @@ final class OverlayManagerServiceImpl {
 
                 if (oi == null) {
                     // This overlay does not exist in our settings.
-                    if (mDefaultOverlays.contains(overlayPackage.packageName)) {
+                    if (overlayPackage.isStaticOverlay ||
+                            mDefaultOverlays.contains(overlayPackage.packageName)) {
                         // Enable this overlay by default.
                         mSettings.setEnabled(overlayPackage.packageName, newUserId, true);
                     }