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