extensions: Don't disable an extension on submit
extensions: Don't disable an extension on submit

We used to lock an extension's details so that it wouldn't be editable,
but this is too difficult and error-prone to do correctly, so just remove
the code that disables the editability of this

magcius/sweettooth,GNOME/extensions-web,GNOME/extensions-web,magcius/sweettooth,GNOME/extensions-web,GNOME/extensions-web