[Glitch] fix: support KaiOS arrow navigation on public pages

Port 1e232e455c to glitch-soc

Signed-off-by: Thibaut Girka <thib@sitedethib.com>

app/javascript/flavours/glitch/packs/public.js

@@ -1,5 +1,6 @@
 import loadPolyfills from 'flavours/glitch/util/load_polyfills';
 import ready from 'flavours/glitch/util/ready';
+import loadKeyboardExtensions from 'flavours/glitch/util/load_keyboard_extensions';
 
 function main() {
   const IntlMessageFormat = require('intl-messageformat').default;
@@ -118,6 +119,9 @@ function main() {
   });
 }
 
-loadPolyfills().then(main).catch(error => {
-  console.error(error);
-});
+loadPolyfills()
+  .then(main)
+  .then(loadKeyboardExtensions)
+  .catch(error => {
+    console.error(error);
+  });