Update API parameter injection

The ReCaptcha module was not injecting its parameters at all, so they
were not showing up in the auto-generated help. This is now fixed.

Also, the API recently added a new parameter to the APIGetAllowedParams hook
to differentiate between fetching the allowed parameter list for help
output and fetching it for processing within the module. ConfirmEdit
only needs to inject the parameters for the former, so it should check
this parameter if available.

Change-Id: Ia8c9a8b882ee3480b71bfb3f2345475506549819
Merge "Update API parameter injection"