Fix touch slop issues on bubble long-press menu.

Also now correctly uses the long-press menu width to determine placement instead of a constant pixel value.

Bug: 144113115

Test: Manual. Enable the long-press bubble menu with "adb shell settings put secure allow_bubble_screenshot_menu 1", create a bubble, and long-press the stack view to show the menu. Should now work
Change-Id: I287a89a852df46269abc0d65b93f28c595d89f65