Fix closing all modals (#12728)

* Fix closing all modals

We used `Modal.closeCurrentModal()` in a bunch of places, in all cases
(as far as I can see: it wasn't commented) we meant to close all open
modals. This swaps that function for one that closes all open modals.

Also types the close reason which claimed to be something in a comment,
of course, was wrong because a load of places passed their own random
string which was never used.

* Force close modals

* Try with minimal changes

* Already had a method for this

* Add test

* More tests

* Unused importsd

src/components/structures/LoggedInView.tsx

@@ -488,11 +488,15 @@ class LoggedInView extends React.Component<IProps, IState> {
                 handled = true;
                 break;
             case KeyBindingAction.GoToHome:
+                // even if we cancel because there are modals open, we still
+                // handled it: nothing else should happen.
+                handled = true;
+                if (Modal.hasDialogs()) {
+                    return;
+                }
                 dis.dispatch({
                     action: Action.ViewHomePage,
                 });
-                Modal.closeCurrentModal("homeKeyboardShortcut");
-                handled = true;
                 break;
             case KeyBindingAction.ToggleSpacePanel:
                 dis.fire(Action.ToggleSpacePanel);