Refs #5976, always display data table footer expand/contract icon. Change expand/contract icon to use lighter theme-based colors.
Refs #5976, fix CSS changes for widgetized reports.
Refs #5976, fix CSS for tests and row evolution.
Only delete assets in tests:run-ui command to speed up UI tests.
Refs #5976, more tweaks to CSS to get different datatable views to look correct.
Refs #5976, another fix for UI tests.
Fixes #5976, quick tweak to CSS in _dataTable.less & update UI test submodule.