[React] Fix ButtonWithIcon usage and theme styling

[clairesunstudio]

ButtonWithIcon component usage and theme styling should be consistent with Button.
See documentation: https://massgovdigital.gitbook.io/mayflower/components/atoms/buttons

Currently, ButtonWithIcon primary usage is not styled properly.

Primary buttons should have solid colors with uppercased button text (this is configurable with a capitalized option for longer button text) Box shadow is used to accentuate the actions. The hover state of the primary button lightens the button background color.

Identify and fix all styling inconsistencies between ButtonWithIcon and Button based on correct Button usage and theme options.