Disable Moblie Data Slice in AP mode

When airplane mode is enabled, users should not be able to
change the value of mobile data. Thus, when airplane mode is enabled,
replace the Slice with a no-op slice explaining why it cannot be
changed.

Fixes:
Fixes: 126726036
Test: robotests
Change-Id: I1c6d95dbb9d0c51247709b9867506c800f5872cd