Change MonitoringCertInfoActivity exported flag to be false.

MonitoringCertInfoActivity can be launched by intent action "com.android.settings.MONITORING_CERT_INFO" and currently only framework use it to show the certification info message. Set it to NOT exported to avoid other apps spoof certificate installed message.

Bug: 233736169
Test: Manual test. Existing unit tests pass.
Change-Id: Id20e7bc8e88efa831b125a182b02eefacfaf875f
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 6fe6832..8b515ef 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -1941,7 +1941,7 @@
         <activity android:name="MonitoringCertInfoActivity"
                 android:label=""
                 android:theme="@style/Transparent"
-                android:exported="true"
+                android:exported="false"
                 android:excludeFromRecents="true">
             <intent-filter android:priority="1">
                 <action android:name="com.android.settings.MONITORING_CERT_INFO" />