Remove unused extensions from Tor Browser for Android

There are 5 unused extensions that are included in Tor Browser Android releases. One of them (Firefox Accounts WebChannel) is enabled by default and could be found on about:performance.

Mozilla Android Components - Ads Telemetry (assets/extensions/ads)
Mozilla Android Components - Firefox Accounts WebChannel (assets/extensions/fxawebchannel)
Mozilla Android Components - Search Telemetry (assets/extensions/search)
Mozilla Android Components - Web Compatibility Interventions (assets/extensions/webcompat)
Mozilla Android Components - WebCompat Reporter (assets/extensions/webcompat-reporter)

In case it is related, these AppConstants are true on Tor Browser for Android: MOZ_DATA_REPORTING, MOZ_TELEMETRY_REPORTING, MOZ_CRASHREPORTER, MOZ_BACKGROUNDTASKS