Fix webapp sidenav issues

[anees-asghar]

These are the issues I have in mind in particular:

• The dropdown items have two arrows
• The dropdown items have different styling (i.e., shadow)
• Clicking on My Card does not close the sidenav for some reason
• The hamburger menu pokes out of the top navbar
• Clicking on Pick Winner slides down the Pick Winner text a bit, but the same isn't true for Workshops (least important, good to have)

Pic for reference:

[anees-asghar]

Decided last one is a non-issue for now.

My Card error is because the My Card page isn't functioning properly. Once the page is fixed, the sidenav item will behave normally.