Some handlers were not correctly unregistered when performing
`unattach`. Thus, `Dialog.handleOpenCloseClick` could be fired more than
once resulting in the dialog been opened and closed immediately
afterwards.
Bug: T186461
Change-Id: I0c3c79644a10d7201ef198f4a4d381c10db4c3af
Adds setWarning(<element>,...) and clearWarning() to mw.mmv.ui.Dialog.
These functions can be used to display a warning ribbon with the given
text in the reuse dialogs, typically when the copyright status of the
file is problematic (e.g. non-free or tagged with {{wrong licence}}).
Bug: T76030
Bug: T71389
Bug: T71557
Change-Id: I7c477c810d391578ec64635357eda97a85ab2954
