<select> Dropdown Buttons in Seven Theme are Too Short

Problem/Motivation

Drop-down <select> elements in the Seven theme are shorter than input boxes/elements in the same row. This is a minor cosmetic issue but very noticeable right out of the box by details-oriented users.

Steps to reproduce

Visit /admin/content:

OR
Open a media browser dialog:

Proposed resolution

Adjust the line-height of the drop-downs so that they line up with the elements/text boxes next to them (1.65rem seems to work).

(All screenshots taken in Microsoft Edge 86.0.622.58 (Official build) (64-bit) on Windows 10.0.19041 Build 19041)

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet