[web] Fit video tag to wrapper

Summary:
This diff solves the video tag fit problem. We could observe small gap between the wrapper and video tag:

Now video tags fit the wrapper:

Linear task: ENG-4401

Test Plan:
The best way to test this is to set background-color: red to wrapper tag using built-in inspection tool in your favorite browser and check if video tag covers wrapper completely.

Tested in Firefox, Chrome, and Safari.

Reviewers: bartek, tomek, inka, kamil

Reviewed By: inka

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8525