Following CLs remove the default value from isFeatureEnabled since the
default value was difficult to use correctly.
For example, there was a code that use isAtLeastT() as default value and
expect feature is always enabled on T+ devices.
However, default value is used only when the device does not have the
flag value or flag value is 0.
So the expectation that the feature is always enabled on T+ devices is
not correct if flag is pushed to the device by mistake or the device is
upgraded from S to T but the flag value is not cleared.
If the feature should be always enabled on T+ devices, `isAtleastT() ||
isFeatureEnabled()` should be used instead of `isFeatureEnabled(
isAtleastT() /* defaultValue*/ )`
After the default value argument is removed from isFeatureEnabled,
isFeatureEnabled is used for default false flag and
isTetheringFeatureNotChickenedOut is used for default true kill switch flag.
automatic_on_off_keepalive_version flag is not configured and devices
don't have this flag value.
So updating to use isTetheringFeatureNotChickenedOut should not have any
behavior change.
Test: m
Bug: 279108992
Change-Id: I43ceab6cc5234bd5a43af3acbd7bd7344844c5a6
0a50c65f75