Replace all instances of Primary Teal with Primary Dark Teal

[seanmiller26]

Our Primary Teal also called $ZooniverseTeal #00979D | RGB 0, 151, 157, 1 does not pass accessibility standards.

Replace any instance of this color with the Primary Dark also called $DarkTeal #005D69 | RGB 0, 93, 105, 1
This color does not seem to be consistent across uses.

https://github.com/zooniverse/mobile/blob/e3217acebf3f4fcb7a8f12fa369b587a634d309f/src/theme.js
https://github.com/zooniverse/mobile/blob/e3217acebf3f4fcb7a8f12fa369b587a634d309f/android/app/src/main/res/values/colors.xml#

This should be completed after #520