Fix: Current pinned post check

[richard-mattinson]

Issue

• Currently pinned post can't be unpinned as they are caught in a check that stops the user from pinning multiple posts. This causes the user to receive a This user already has a pinned post error when attempting to unpin their post.

  Fix

• Add id: { not: postId } to allow the currently pinned post to update if it is passed to the setIsPinned function.

[vherus]

Approved