Set paywall panel background black.

Co-authored-by: Cursor <cursoragent@cursor.com>

zoom_app/ViewController.swift

@@ -3721,7 +3721,7 @@ class ViewController: NSViewController {
         let panel = NSView()
         panel.translatesAutoresizingMaskIntoConstraints = false
         panel.wantsLayer = true
-        panel.layer?.backgroundColor = palette.sectionCard.cgColor
+        panel.layer?.backgroundColor = NSColor.black.cgColor
         panel.layer?.cornerRadius = 0
         styleSurface(panel, borderColor: NSColor.clear, borderWidth: 0, shadow: false)
         root.addSubview(panel)