Add a test for metered/non-metered mobile network am: 2685c929f4 am: bbb828ef8e am: 7bd953a52e am: 0ae456a03f

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1779527

Change-Id: Ia6a2c03e6201ba3f61f7f6dfc3576c57ccf88fa9