[Fix] Pin icon should not be visible to users without pin permission (revised)

[thesynthax]

Brief Title

Pin icon should not be visible to users without the pin permission like in main Rocket.Chat application. Check #518, #519 and #520 for complete details

Acceptance Criteria fulfillment

• [x] Pin Icon is now not visible to users not having Pin Permissions.

Fixes #519

Video/Screenshots

P.S: This PR is a revision of #520 after #518 is merged. Following this, #520 will be discarded.

[thesynthax]

@Spiral-Memory @sidmohanty11 please have a look.