Don't remove SYSTEM_FIXED for intentional fixed grants to critical apps.

See b/208785537#comment11.

Bug: 208785537
Bug: 206556385
Bug: 183537857
Bug: 208785537
Test: presubmit
Change-Id: Iaf5e2a0d86259805a9ef03f8f1baa14dd8c58da0
Merged-In: Iaf5e2a0d86259805a9ef03f8f1baa14dd8c58da0
(cherry picked from commit e6f07a4fb2)

services/core/java/com/android/server/pm/permission/DefaultPermissionGrantPolicy.java

@@ -435,7 +435,8 @@ final class DefaultPermissionGrantPolicy {
                     || !pm.isGranted(Manifest.permission.READ_PRIVILEGED_PHONE_STATE,
                             pkg, UserHandle.of(userId))
                     || !pm.isGranted(Manifest.permission.READ_PHONE_STATE, pkg,
-                            UserHandle.of(userId))) {
+                            UserHandle.of(userId))
+                    || pm.isSysComponentOrPersistentPlatformSignedPrivApp(pkg)) {
                 continue;
             }