fix: Text same color as background

[Dbardgett]

Problem

When operating the GUI from my M1 Macbook Pro, the text appears to be the same color as the background in several windows including:

• CV Experiment Creator
• Parts of CA Experiment Creator
• LSV Experiment Creator
• The list of loaded experiments in the main window
• The drop-down list of ports to for connecting the potentiostat (unsure if the text color is identical to background color or if there just isn't any text there)

Proposed solution

Change the color of the problem text or the background to be different from each other.