[e.cash] Adjust image height on core-tech

Summary:
The eToken image on /core-tech was too large and all of the images have the same height.
Adding an optional height prop so we can adjust as needed

Test Plan: preview the site and check /core-tech. See all the images look good

Reviewers: #bitcoin_abc, Kronkmeister

Reviewed By: #bitcoin_abc, Kronkmeister

Subscribers: Kronkmeister

Differential Revision: https://reviews.bitcoinabc.org/D16157