This commit clear the calling identity before accessing the
DeviceConfig in ConnectivityService#dump().
The calling package of DeviceConfig.getProperties() comes from
ActivityThread.currentApplication(). In ConnectivityService#dump(),
the caller is ConnectivityService. It's OK to access DeviceConfig
from ConnectivityService. The same scenario applies to an app with
proper permission accessing DeviceConfig from its own context.
However, if cts would like to verify design by calling
ConnectivityService#dump(), the calling uid will comes from the
binder but package name will stay as ConnectivityService which
is 'android'. This will result in a SecurityException says that
the package does not match the uid and failed the test.
Bug: 255231779
Test: atest CtsNetTestCases FrameworksNetTests
Change-Id: I257e246b1cbf3b8a93bee2c326055ced9dfde588
18a6e8cf2f