[landing] Keep hero TextLoop to two lines

Summary:
Use clamp to interpolate between font-sizes that ensure that things remain on two lines

now depends on D3430

Test Plan:
Set the text to "gaming guilds" (the longest one) and made sure the text never broke to three lines. Also checked iPhone 13 mini to make sure that it looks okay at a very low breakpoint

Reviewers: def-au1t, palys-swm, varun, benschac

Reviewed By: palys-swm, benschac

Subscribers: ashoat, Adrian, karol-bisztyga

Differential Revision: https://phabricator.ashoat.com/D3392