Revert "Bug 911696 - [Dialer] [Flatfish] hide dialer app in homescreen if no telephony support"

This reverts commit 4cfe3660a8f293f54c111d07fca5cec6089bd32a.
Merge pull request #12303 from KevinGrandon/kevin-v1.2

Revert "Bug 911696 - [Dialer] [Flatfish] hide dialer app in homescreen if no telephony support" r=fabrice
Revert "Merge pull request #12234 from EragonJ/bug-914317"

This reverts commit bda5c4a902793934467b689a118a2c68f745706e, reversing
changes made to bc85e07011c2c40986693657fa7647ee5c9f8eea.
Merge pull request #12323 from nullaus/891724-supportcontactcustomization

bug 891724