settings_connectivity_flags is used from system_ext app

As a system_ext app is using the flags, the flags must be in the
system_ext container instead of the system container.

Bug: 385213580
Test: "adb shell aflags list" must not be changed.
Flag: EXEMPT refactor
Change-Id: I46123b93909acc1e1b2e84ac4fe7898ed5243fc5