Dynamic broadcast receivers that are not exported need to be filtered in checkBroadcastFromSystem

When the system code sending non-protected broadcast,
if it's dynamic broadcast receiver is not exported,
the wtf log of sending non-protected broadcast should not be printed.

Bug:263210319

Test:A system code, for example com.android.settings
step1:send a non-protected broadcast but with packageName to itself;
step2:it registers a dynamic broadcast receiver with Context.RECEIVER_NOT_EXPORTED to receive this broadcast.

Change-Id: Ie7e359d1ae079be0d444c72791ff1b2a892b71bb

services/core/java/com/android/server/am/ActivityManagerService.java

@@ -13529,7 +13529,7 @@ public class ActivityManagerService extends IActivityManager.Stub
                     }
                 } else {
                     BroadcastFilter bf = (BroadcastFilter)target;
-                    if (bf.requiredPermission == null) {
+                    if (bf.exported && bf.requiredPermission == null) {
                         allProtected = false;
                         break;
                     }