Adapt Sidebar Upload button to new design

[Faithkenny]

Overview

We need to adapt what we have currently in Production to what exists in our Figma file. This ticket differentiates how it current works, and how it should work

How it currently works

Old.Sidebar.upload.-.hover.mp4

Here's how it should work

• Hovers from an outline button to blue-filled button. This is the only time a main action button in the ODE isn't primarily dark.
• Play this Prototype

new.Sidebar.-.upload.mp4

[guergana]

This has been changed in #620