Clean up page number parameter for AJAX pagination in bp_filter_request()

[dcavins]

The pagination click handler in buddypress.js sends kind of an ugly pagination parameter because of the way it parses the page number from the pagination link. (It sends something like $_POST['page']: 2&num ). This can cause problems for BP Group Hierarchy in certain cases, so I suspect it might cause trouble for other plugins, too.

My patch just changes the parsing a bit so that the $_POST['page'] parameter sent is only the page number.

[dcavins]

Clean up page number sent in AJAX pagination requests

[dcavins]

In 9809:

Clean up page param in AJAX pagination request.

When including the page parameter in AJAX pagination requests, strip
out trailing arguments. E.g.: instead of sending '2&num,’ send '2'.

Fixes #6394.