[Wi-Fi] Update "Factory MAC" to "Device MAC" in strings.

As a follow-up to b/133466540, we should change "Factory MAC" to "Device MAC" in the strings to align with the language that we used for Q.

Sol: change the string naming.

Bug: 143151237
Test: Manual visual test to check if the strings changed correctly or not.
Change-Id: I0bba14d12d5d0ab2fa0c137e4576dd46878df031
4 files changed