Automatically trigger passkeys on login view (#3307)

Add an on-load handler to pkhtml.js so that when the partial
view is displayed passkey auth is automatically prompted for.
If the users browser blocks this event, the fallback manual
buttons still exist.

server/core/static/pkhtml.js

@@ -40,3 +40,8 @@ try {
     });
 } catch (_error) {};
 
+try {
+    window.addEventListener("load", (event) => {
+        asskey_login()
+    });
+} catch (_error) {};