feat: show warning before blocking followed channel (#5615)

src/widgets/DraggablePopup.hpp

@@ -38,10 +38,18 @@ protected:
     // button pixmap
     void togglePinned();
 
+    /// Ensures that this popup is pinned (if it's expected to close automatically)
+    ///
+    /// @returns `true` if the popup was pinned as a result (i.e. if the popup
+    ///          was unpinned and said to automatically close before)
+    bool ensurePinned();
+
 private:
     // isMoving_ is set to true if the user is holding the left mouse button down and has moved the mouse a small amount away from the original click point (startPosDrag_)
     bool isMoving_ = false;
 
+    bool closeAutomatically_ = false;
+
     // startPosDrag_ is the coordinates where the user originally pressed the mouse button down to start dragging
     QPoint startPosDrag_;