This is a pretty simple question but I can't seem to find an answer. I have created a long text area in Salesforce and set the visible lines to 2:

But when viewing the field in a lead record - all rows are shown:

Referring to the documentation for the visible lines attribute:
For long text area fields, set the number of lines to be displayed on edit pages.
So I can set the number of visible lines on the edit page no problem, but how do I set the number of visible lines for the text area long field on the lead details page?