Alignment issues when forcing large font sizes in Safari

[sbates-idrc]

If "never use font sizes smaller than" is checked in Safari's accessibility settings, and the minimum size is set to "18" or "24", the alignment of various elements breaks.

Here's a screenshot with Chrome on the left and Safari on the right.

Affected components include:

• The character icon in the program block editor is not aligned with its background
• The plus sign in the expanded add node is not aligned with its border
• The keyboard and theme selector icons are out of alignment (and too small)
• The refresh button is not aligned with the other buttons
• The square in the stop button is not aligned with its border

Original Jira issue: https://fluidproject.atlassian.net/browse/C2LC-551