FVP-02-013 WP5: Android app exposes sensitive data to system logs

[bakulf]

It was found that the Android app makes frequent use of logging features to be able to
monitor events. However, this can be considered a bad practice, especially in production
environments where tokens and codes of Mozilla VPN users might be accessible by
third-parties.
In case the device is connected to the computer with debugging enabled via USB, an
attacker may be able to get access to the logs via adb logcat. From there, extraction of
user-tokens may be achievable. Note that apps with system privileges are able to
access logs directly on rooted devices.

┆Issue is synchronized with this Jira Task

[bakulf]

Maybe this can be considered a dup of https://github.com/mozilla-mobile/mozilla-vpn-client/issues/811