profiles: blink-common: fix u2f

udev rules may set permissions in /dev/... to enable ordinary users to
access the hardware token.
This fix checks whether u2f is enabled in firejail.config in order to
keep this permission change inside the sandbox.

etc/profile-a-l/blink-common.profile

@@ -30,7 +30,7 @@ apparmor
 caps.keep sys_admin,sys_chroot
 netfilter
 nodvd
-nogroups
+?BROWSER_DISABLE_U2F: nogroups
 noinput
 notv