float: Add drag threshold in the menu

This adds a threshold only in the menu, to allow for easier button
presses.

Test: added
Fixed: b/273800202
Change-Id: I674aa87016e0e1c1b0fd60dce38ad2adce90f873
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4350775


Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Commit-Queue: Sophie Wen <sophiewen@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1118938}