feat(settings): add full width to API config manager dropdown

Add a CSS class to make the API config dropdown take up the full
width of its container. This improves the layout and appearance
of the settings page.

webview-ui/src/components/settings/ApiConfigManager.tsx

@@ -219,6 +219,7 @@ const ApiConfigManager = ({
 								value: config.name,
 								label: config.name,
 							}))}
+							className="w-full"
 						/>
 						<VSCodeButton
 							appearance="icon"