firefox: toolkit.telemetry.enabled locked to true

[xerz-one]

According to Mozilla, Firefox uses toolkit.telemetry.enabled to collect "somewhat more information" about a web browser's activity and report it back to Mozilla. It should only be enabled on beta, aurora, and nightly builds, and it's always a locked setting. However, on the stable builds delivered by Void, toolkit.telemetry.enabled is set to true.

Take into account that data reporting is (theoretically?) disabled because of the build settings, and so Firefox tells the user in about:preferences.

[jnbr]

Telemtry is disabled (see #11517) for our firefox builds so this is not an issue.

[xerz-one]

I know it's disabled and I said so. It would tho, at the very least, give peace of mind. I should also check on whenever logs are kept locally when telemetry is disabled.