Use 'set-standby-bucket' instead of 'set-inactive' command.

When 'set-inactive' command is used, it is possible for the
test app to get into the NEVER bucket as it wouldn't be
recorded as used by the user in some cases.

Bug: 298816567
Test: atest tests/cts/hostside/src/com/android/cts/net/HostsideRestrictBackgroundNetworkTests.java
Change-Id: If2667a07629b38395d0fed99771488d0900caf18