environment/permissions: Fix permission popup not showing

`window.screen` is not available in manifest v3, causing the prompt window fallback method to fail.

lib/environment/background/permissions.js

@@ -24,9 +24,11 @@ async function makePromptWindow({ permissions, origins }) {
 
 	const width = 630;
 	const height = 255;
-	// Display popup on middle of screen
-	const left = Math.floor(screen.width / 2 - width / 2);
-	const top = Math.floor(screen.height / 2 - height / 2);
+
+	// Get the current window's dimensions and calculate center position
+	const { width: screenWidth, height: screenHeight } = await chrome.windows.getCurrent();
+	const left = Math.floor(screenWidth / 2 - width / 2);
+	const top = Math.floor(screenHeight / 2 - height / 2);
 
 	const { tabs: [{ id }] } = await apiToPromise(chrome.windows.create)({ url: url.href, type: 'popup', width, height, left, top });