Convert gitlab webapp files to typescript

[ayusht2810]

Summary

• Convert link_tooltip component to typescript #424
• Convert rhs_sidebar component to typescript #425
• Convert sidebar_buttons component to typescript #430
• Convert sidebar_header component to typescript #431
• Convert user_attribute component to typescript #434
• Convert team_sidebar component to typescript #435
• Convert utils folder files to typescript #436
• Convert icons component in images folder to typescript #437

There are other JavaScript files that have not had tickets created for them yet. Feel free to look into other files if you would like. We will create the issues as needed. Thank you!

Main issue mattermost/mattermost#25781

[the-illuzion]

Hey @ayusht2810 @mickmister can you assign these two issues to me

[mickmister]

Hey @the-illuzion! Thanks for your interest in contributing! I've assigned to you #424. In other to assign #425, you'll need to comment on the ticket so GitHub will allow me to assign you.

Thank you @the-illuzion!