clientmod: parameterize EnableTlsTrustBypass via template placeholder

Render the flag from {ENABLE_TLS_TRUST_BYPASS} instead of hardcoding
true, so the launcher's opt-in toggle controls it. Off by default
since Localtunnel/Tunnelto serve valid certs.

DorkNet.ClientMod/dorknet-clientmod.json.template

@@ -4,5 +4,5 @@
   "PhotonAppId": "{PHOTON_APPID}",
   "PhotonVoiceAppId": "{PHOTON_VOICE_APPID}",
   "PhotonCloudRegion": "{PHOTON_REGION}",
-  "EnableTlsTrustBypass": true
+  "EnableTlsTrustBypass": {ENABLE_TLS_TRUST_BYPASS}
 }