GH-88081
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Validate extension JSON: Error: Field 'classes/EditorPlugin/methods/add_control_to_bottom_panel/arguments': size changed value in new API, from 2 to 3.
Validate extension JSON: Error: Field 'classes/EditorPlugin/methods/add_control_to_dock/arguments': size changed value in new API, from 2 to 3.

Added optional argument to add_control_to_bottom_panel and add_control_to_dock to specify a shortcut that toggles the bottom panel/dock's visibility.
Compatibility method registered.
