Enhancement in pin post functionality

[aashimawadhwa]

Describe the bug
currently the pin post is not working in the posts section under dashboard.

To Reproduce
Steps to reproduce the behavior:

1. navigate to organization dashboard
2. click on post
3. click on hamburger button (3 vertical dots) in the detailed post modal
4. find pin post functionality

Expected behavior
The pin post should pin the post and keep it on the top with a pin icon and sorting of post should not be affected with it. pinned post should remain on top followed by the other posts.

Actual behavior
pinning of post is not functioning

Potential internship candidates
Please read this if you are planning to apply for a Palisadoes Foundation internship PalisadoesFoundation/talawa#359

[chandel-aman]

@aashimawadhwa Can I work on this issue?