[landing] clean up competitor comparison UI

Summary:
As I was inputting copy for one of the competitors I came across some modals/elements that were not super clean visaully. Spoke with @ted and he gave me some tips on how to clean things up.

1. We should make the padding for the modal container 32px all around
2. The descriptions in the competitor feature comparison modal should not have a min height
3. The dividers in the competitor feature cards that have are a tad off

Linear task: https://linear.app/comm/issue/ENG-4346/remove-min-height-for-competitor-feature-comparison-modal

Depends on D8176

Test Plan:
Please see the screenshots below to see that each point in the summary was addressed:

We should make the padding for the modal container 32px all around

Before:

After:

The descriptions in the competitor feature comparison modal should not have a min height

Before:

After:

The dividers in the competitor feature cards that have are a tad off

Before:

After:

Reviewers: atul, kamil

Reviewed By: atul, kamil

Subscribers: ashoat, tomek, ted

Differential Revision: https://phab.comm.dev/D8477