Improve the readability of the view mode and form mode page

Problem/Motivation

The columns for the different view mode and form mode entity types are not really aligned across entity types and with the introduction of a description column #3364659: Give display modes a description things got a bit more challenging cognitively (*I don't mean the description was the wrong thing to add. I really like it's addition but it jut introduces a potential additional readability problem in case the description gets long and verbose)

If you compare the rows for the different entity types vertically they don't look consistent since their columns aren't horizontally aligned. That way there is sort of a constant visual distraction by having an horizontal shift of the column widths across the different entity types sections. Those shifts also lead to different sized horizontal gaps between the columns. for example in the viewmodes.jpg the gap between "test" (name column) and "description about a test" (description column) is huge, same as the gap to the corresponding edit button. the gap for view modes without any description is even larger. if you try to keep the line visually with the straw test it is challenging (also due to the fact that the separating lines have a color contrast of 1.5:1 which might be too light) . and if you are moving down the operations column with the mouse you dont have to move vertically but also horizontally when you get within a new entity type section to be able to reach any of the new region's edit buttons.
And in general it seems the width of the different columns between entity type sections differs significantly. For content the name column is extra wide compared to other entity types. The width of the description and operations column is more or less the same width.

And one extreme edge case but if you add a long description and you are using a wide screen monitor you will end up with a line length of 648 characters for a 36" monitor. The goal in regards of meeting the AAA WCAG2.1 SC1.4.8 C20 is having a line length of around ~80 characters.

The problem was touched during the discussion of #2721727: Allow user to add display modes from respective field UI's. in todays usability meeting. That issue #3395398: Drupal Usability Meeting 2023-10-27 will have a link to a recording of the meeting. For the record, the attendees at today's usability meeting were @AaronMcHale, @anmolgoyal74, @benjifisher, @rkoller, @shaal, @simohell, and @worldlinemine.

Steps to reproduce

• Go to /admin/structure/display-modes/view

Proposed resolution

A few suggestion to improve the current state:

• make the column widths consistent across entity types
• try to avoid large gaps
• set a maximum width in particular for the description column to avoid such extreme line lengths illustrated in 36inchdescription.jpg

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet