Fix usage of ToggleBookmarkAction in split windows scenario

[matthiasblaesing]

It was observed, that the "Goto Bookmark" actions cause the goto action in the correct window (the focused one or the one the toolbar is located in), while the "Toogle Bookmark" action invokes the action for the first editor window.

The implementation of the ToggleBookmarkAction implies that the button should reflect whether or not there s a bookmark on the current line (rendering the button active/pressed when there is a bookmark). It was observered, that this does not work.

So instead of fixing the complex implementation, the implementation for ToggleBookmarkAction was aligned with the "GotoBookmarkAction", inheriting the "find the right text component" behavior from BaseAction.

Closes: #4155