[landing] introduce multi paragraph functionality in CompetitorFeature

Summary:
The new copy for the long matrix feature comparison descriptions introduces multiple paragraphs. This diff introduces new logic in CompetitorFeature so that it can handle spacing multiple paragraphs the "right way" (not using spaces/newlines, but instead using separate elements and spacing them through margin/padding)

Depends on D8024

Test Plan:
Please see the screenshots/demo below:

Single paragraph:

multi paragraph:

demo:

Reviewers: atul, kamil

Reviewed By: kamil

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8537