FXVPN-328: Enable telemetry by default (#175)

This PR enables telemetry in the extension by default, even if the
client is not installed. Note that in this state, although telemetry is
'enabled', pings won't be sent to Glean until the client has been
installed and is able to do so.

src/background/vpncontroller/states.js

@@ -217,7 +217,7 @@ export class vpnStatusResponse {
 }
 
 export class VPNSettings {
-  extensionTelemetryEnabled = false;
+  extensionTelemetryEnabled = true;
 }
 
 export class BridgeResponse {