Improve Post comments section UX

[juandiegox21]

• 1. When you are reading the comments of a post any change that occurs for that post in firestore (Likes, comments) results in the comments section getting hidden.

• 2. A scrolling view should be added for displaying the comments of a post.

• 3. The "Leave a comment" box should be displayed right below the post and not at the bottom of the comments in a post.