[Drag & Drop blocks] Allow dragging from block toolbar

[fluiddot]

Description

Currently, blocks can be dragged by long-pressing over their content area. However, if the block is selected, the dragging area is limited to the content itself, without taking into account extra areas like the block toolbar. This behavior might be confusing to users, so it would be great if we could enable dragging also from the block toolbar.

NOTE: It's important to note that some of the buttons from the block toolbar, like the up/down arrow buttons, can be long-pressed to display extra options on each case. This behavior should be preserved, so long-pressing over the buttons shouldn't start the dragging.

[fluiddot]

Addressed in WordPress/gutenberg#40886.