mod_http_admin_api: Tweak token session to please module:may() module:may() checks for type == "c2s", but mod_tokenauth does not currently include that or most common session properties. Fixes a traceback resulting from a different code path where module:may() tries to index event.stanza, which does not exist for http events.

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labels:
- 'Stage-Alpha'
summary: Implements BOSH pre-bind
...

For why this can be useful, see
https://metajack.im/2009/12/14/fastest-xmpp-sessions-with-http-prebinding/

# To enable this module

Add `"http_prebind"` to `modules_enabled` on an anonymous virtual host.

This only works on anonymous ones for now.