Do not interact with `require()` while `define.amd` is unset

Do not interact with `require()` while `define.amd` is unset

During development I noticed that regularly `focus-trap` failed to load
properly, likely due to being pulled in by some module while `define.amd` was
unset and thus failing to register itself as a module due to the UMD header.

Fix this by moving the `define.amd` unsetting and resetting into dedicated
`<script>` tags that wrap jQuery + WCF.js and nothing else.