Main header broken on smaller mobile device sizes

[jtomeck]

The above screenshot is taken using iPhone 12 Pro size (390px wide). I already made suggestions in #1764 so I won't address that portion here, but for the main header I suggest:

1. Hide the word "DANDI" in the logo on mobile.
2. The button and avatar don't need to be so big
   • Reduce padding on button
   • Use "+" icon instead of the word "NEW" so it reads "+ DANDISET"
   • Reduce padding or dimensions of Avatar