[4.0] Move event listener from joomla-toolbar-button to button element

[SharkyKZ]

Fixes #29820.

Summary of Changes

Moves event listener from joomla-toolbar-button element to actual clickable button.

Testing Instructions

node build.js --compile-js required.
Go to any backend view containing toolbar buttons.
Click a couple of pixels below or above a button.

Actual result BEFORE applying this Pull Request

Button clicked.

Expected result AFTER applying this Pull Request

Button not clicked.
Also check that buttons continue to work properly.

Documentation Changes Required

No.

[Quy]

I have tested this item ✅ successfully on c653e7f

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/29852.}

[Quy]

RTC

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/29852.}

[wilsonge]

Thanks!

[SharkyKZ]

@Fedik I'm aware this was related to styling. But I think this PR is semantically correct. joomla-toolbar-button is not a button and requires a button or a element inside, according to this comment:

joomla-cms/build/media_source/system/js/joomla-toolbar-button.w-c.es6.js

Lines 36 to 37 in 1f24603

	// We need a button to support button behavior,
	// because we cannot currently extend HTMLButtonElement