WifiPermissionsUtil: Check location mode for current fg user

a) Use the WifiPermissionsUtil.isLocationModeEnabled() for all location
mode checks in the wifi stack.
b) Check the current fg user's location mode instead of the system user (0).

Bug: 121336053
Test: ./frameworks/opt/net/wifi/tests/wifitests/runtests.sh
Change-Id: I9c20b5f5f0c11abbf6e6bba2bbfd5ff4dd6df22c
11 files changed