Change the default value of the flag to true as discussed via chat

Flag is already enabled on Trunkfood/Droidfood devices, and has soaked
for long enough to enable by default.

Bug: 379988507
Test: atest NetworkSecurityUnitTests
Change-Id: Ib0a9e3023ca46f5ce7a257af310789e1d25eb24d
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
index 92b2b09..eef867c 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package com.android.server.net.ct;
 
 import android.annotation.RequiresApi;
@@ -36,7 +37,8 @@
      */
     public static boolean enabled(Context context) {
         return DeviceConfig.getBoolean(
-                        Config.NAMESPACE_NETWORK_SECURITY, Config.FLAG_SERVICE_ENABLED, false)
+                Config.NAMESPACE_NETWORK_SECURITY, Config.FLAG_SERVICE_ENABLED,
+                /* defaultValue= */ true)
                 && Flags.certificateTransparencyService();
     }