Enable Touch Feedback Experiment by default
Change touch feedback switch to be a disabling switch. Update locations currently referencing the switch. Update unittests to no longer set the flag as it will be on by default.
TEST=SystemTrayTest.TrayPopupItemContainerTouchFeedback, SystemTrayTest.TrayPopupItemContainerTouchFeedbackCancellation, TrayDetailsViewTest.HoverHighlightViewTouchFeedback, TrayDetailsViewTest.HoverHighlightViewTouchFeedbackCancellation, MenuButtonTest.TouchFeedbackDuringTap, MenuButtonTest.TouchFeedbackDuringTapCancel
Review URL: https://codereview.chromium.org/
752163003
Cr-Commit-Position: refs/heads/master@{#306298}