A11y fix: remove clickable hint from Talkback description when no click listener is set on Balloon

[matt-clarke-wooliesx]

🎯 Goal

The goal of this PR is to improve the correctness of screen reader hints for Balloons that do not have a click listener set (via Balloon::setOnBalloonClickListener).

Currently, Talkback will incorrectly say "double-tap to activate" for these Balloons. This change removes that part of the Talkback description without affecting the rest of it.

🛠 Implementation details

Currently setOnBalloonClickListener() always sets a "wrapper/parent" click listener on the Balloon, even when the click listener argument is null. Talkback incorrectly infers from this that the Balloon is clickable, despite it possibly being a no-op click listener.

This change only sets the parent click listener when clicking would likely have some noticeable effect. More specifically, if the onBalloonClickListener argument is non-null or if builder.dismissWhenClicked is true.

android:focusable="true" was set on the balloon wrapper FrameLayout in order to maintain the existing Talkback behavior of reading out the text contents of the Balloon.

✍️ Explain examples

In the example below, tapping the highlighted balloon with Talkback on would currently read out:
"skydoves. Love coffee, music, magic tricks and writing poems. Double-tap to activate."

After this change:
"skydoves. Love coffee, music, magic tricks and writing poems."

Preparing a pull request for review

Ensure your change is properly formatted by running:

$ ./gradlew spotlessApply

✅

Please let me know if you have any requests for improvement for this to be acceptable to merge.

[skydoves]

Hey @matt-clarke-wooliesx,
This looks perfect! Thanks for your contribution 😄

[matt-clarke-wooliesx]

Thank you @skydoves !