Attempt to fix performance regression since 5164254

The wrong condition in StatusBarManagerService#disabledLocked, which causes
CommandQueue#disable(disable1, disable2, true) dispatches to many callbacks
and draw many unnecessary frames. Also add a check to prevent from setting
notification disable flags on external displays since we don't enable
notifications on external displays now.

Fixes: 120625457
Test: atest
google/perf/jank/SystemUI/UbSystemUIJankTests:android.platform.systemui.tests.jank.SystemUiJankTests#testLaunchSettings

Change-Id: I2092ee5b2df1c9116c306af526add724e64209aa