[e.cash] Prevent core tech section height jumping

Summary:
due to different content length the core tech section causes background shifts when going through
the different items.

Adding a min fixed height to the container to avoid this

Test Plan: preview site and check it out

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D16780