Give the video effects more room in the Add effect menu

With eight video effects their list filled its 110-pixel cap, and the menu's
headings take more than the 120 pixels the height test allowed for them.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/gui/window.cpp

@@ -1779,8 +1779,8 @@ Gtk::Widget& EffectorWindow::buildChainSection() {
 // The tallest each part of the menu of effects grows before it scrolls, in
 // pixels: together, with their headings, short enough to open below a button
 // near the top of a small screen.
-constexpr int addMenuImageHeight = 330;
-constexpr int addMenuVideoHeight = 110;
+constexpr int addMenuImageHeight = 300;
+constexpr int addMenuVideoHeight = 150;
 
 // One entry per registered effect, so a new effect shows up here without this
 // file knowing anything about it. The image effects and the video effects