[adbwifi] SysUI: Add WifiDebuggingActivity.

This will prompt the user whether they trust the current wireless access
point when enabling wireless debugging.

Bug: 147814644

Test: make
Change-Id: I56a7c022f26d4e3d93a22d9022f19f1b8d997d70
Merged-In: I56a7c022f26d4e3d93a22d9022f19f1b8d997d70
Exempt-From-Owner-Approval: cherry-pick