Reduce unnecessary config change when setting locale

The caller may only set the config fields that it request to change.
And the non-screen-layout-direction bits should be only computed by
display (DisplayContent#computeScreenConfiguration). Otherwise
when applying global config to default display, it will lead to an
unnecessary extra change CONFIG_SCREEN_LAYOUT which increase the
latency of changing locale.

Bug: 430213501
Flag: EXEMPT bugfix
Test: Change locale from Settings. The event log should only
      contain one configuration_changed.

Change-Id: I020ef69edb5b90cf1ea9937ffc438191036fcd8c