FakeVim: only block suggestion when fakevim is in use

This fixes the issue that no copilot suggestion were shown after
switching documents.

Change-Id: Ic81bfbe266877964eeaf688d9915a7937607118b
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/plugins/fakevim/fakevimplugin.cpp

@@ -1587,6 +1587,8 @@ void FakeVimPluginPrivate::editorOpened(IEditor *editor)
 
     handler->modeChanged.set([tew, this, editor](bool insertMode) {
         HandlerAndData &handlerAndData = m_editorToHandler[editor];
+        if (!handlerAndData.handler->inFakeVimMode())
+            return;
 
         // We don't want to show suggestions unless we are in insert mode.
         if (insertMode != (handlerAndData.suggestionBlocker == nullptr))