Add option to set TrayBubbleView as activatable

This CL adds an init_param option to make a `TrayBubbleView` activatable
on click or tap events.
This CL does not change any current behavior.

Additional context:

TrayBubbleViews are not activatable by default, the RerouteEventHandler
sets them as activatable when a keyboard event is detected so the
bubble can get focus. For some bubbles like the NotificationCenterBubble
we need them to get focus after clicks/taps like when clicking on a
reply button on a notification. This is currently handled in an obscure
way by a `ClickActivator` in `NotificationViewBase`. We should handle
this in TrayBubbleView logic instead and clean up `ClickActivator`.

Bug: 329712701

Change-Id: I3d858c2dcae661b879c97daa2f1d82c7033442c6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5372421


Reviewed-by: Andre Le <leandre@chromium.org>
Reviewed-by: Jiaming Cheng <jiamingc@chromium.org>
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1273116}