Don't update app idle rules on updateRulesForRestrictPowerUL().

updateRulesForRestrictPowerUL() should only affect the global
rules (Doze and Battery Saver), while app idle is an app-specific
rule. Such call was delaying setDeviceIdle() in O(100ms).

BUG: 31281543

Test: cts-tradefed run commandAndExit cts -m CtsHostsideNetworkTests -t com.android.cts.net.HostsideRestrictBackgroundNetworkTests#testAppIdleNonMetered_enabled
Test: cts-tradefed run commandAndExit cts -m CtsHostsideNetworkTests -t com.android.cts.net.HostsideRestrictBackgroundNetworkTests#testAppIdleNonMetered_whitelisted
Test: cts-tradefed run commandAndExit cts -m CtsHostsideNetworkTests -t com.android.cts.net.HostsideRestrictBackgroundNetworkTests#testAppIdleNonMetered_blacklisted
Test: cts-tradefed run commandAndExit cts -m CtsHostsideNetworkTests -t com.android.cts.net.HostsideRestrictBackgroundNetworkTests#testAppIdleMetered_enabled
Test: cts-tradefed run commandAndExit cts -m CtsHostsideNetworkTests -t com.android.cts.net.HostsideRestrictBackgroundNetworkTests#testAppIdleMetered_whitelisted
Test: cts-tradefed run commandAndExit cts -m CtsHostsideNetworkTests -t com.android.cts.net.HostsideRestrictBackgroundNetworkTests#testAppIdleMetered_disabled

Change-Id: I32ad6853a6d88e2709538d00cd1e77b96d331b2d