msglist: Stop double-%-encoding off-realm links which broke downloads (iOS)

This doesn't re-introduce #3315 (SafariView complaining on non-ASCII
URLs) because all non-ASCII characters are still percent-encoded.
That gets done by the URL constructor, which we started using in
this codepath in the previous commit. See discussion and more
detail:
  #4136 (comment)

Fixes: #4136

Author: chrisbobbe

src/utils/openLink.js

@@ -7,7 +7,7 @@ import type { BrowserPreference, GlobalSettingsState } from '../types';
 /** Open a URL in the in-app browser. */
 export function openLinkEmbedded(url: URL): void {
   if (Platform.OS === 'ios') {
-    WebBrowser.openBrowserAsync(encodeURI(url.toString()));
+    WebBrowser.openBrowserAsync(url.toString());
   } else {
     NativeModules.CustomTabsAndroid.openURL(url.toString());
   }