failureEnablingIpForwarding verifies that TetheringMetrics sends one
more error report than it should. This extra verification is caused by
any(class) being passed into the mock WifiManager.startTetheredHotspot,
which does not match null even though the actual code passes in a
null. This results in an extra failure that causes the extra error
report call.
Fix this by replacing any(class) with null, and removing the extra error
verification.
Bug: 216524590
Test: atest TetheringTest
Change-Id: I93986a999d573a186696e54793563e2be8405f39
3b6ee54cf6