Add reconnectCell util, refactor reconnectWifi

Add a utility to reconnect mobile data, and refactor toggleWifi to match
it.

The new reconnectWifi utils do not support turning wifi on and back off
anymore, but this was dead code as no test was using it (wifi is
supposed to be connected before starting tests).

Bug: 253698734
Test: atest
Change-Id: I2b8b8d186d05bb57c6a45d872febc54def8c6d59