Credit offline contribution to an event PCP

When an offline donation is received and entered via Contribution > New Contribution, the "credit this contribution to a personal campaign page" link only functions for Contribution PCPs. Event PCPs are unavailable in the AJAX list.

This is because the code in CRM_Contact_Page_AJAX::getPCPList() always joins civicrm_pcp to civicrm_contribution_page instead of using one of civicrm_contribution_page or civicrm_event depending on the PCP type.