[landing] Make buttons variable width
Summary:
The <Button> component in landing is used in two places:
- It's used in the team page. From testing on Chrome, I can see that flex-basis has no effect there. Chrome explains why:
- The main use is the download page. I'm about to introduce a new button, so I actually want to change the grid layout there. See test plan for before/after
Test Plan:
Check how team and download pages look in my local dev environment
| before | after |
 |  |
Reviewers: varun
Reviewed By: varun
Subscribers: tomek
Differential Revision: https://phab.comm.dev/D13624