Sticky escalation for non-moderators

[johnjamesjacoby]

Non-moderators are able to escalate the sticky-status of a new topic by spoofing the 'bbp_stick_topic' $_POST parameter, as the _new_ and _edit_ handlers are missing a 'moderator' capability check.

iirc, the long term plan was to use a dedicated 'stick_topics' capability, and map it to moderate (this is how bbPress 1.x handled this) though it seems overkill for core to map this, as a plugin would need to remap it to change the behavior anyways.

Patch imminent, adds cap checks to the _new_ and _edit_ handlers.

[johnjamesjacoby]

In 5019:

In bbp_new_topic_handler() and bbp_edit_topic_handler(), restrict sticky topic actions to users with 'moderate' capability. Fixes #2366.