fix: adjust the styling of dropdown and multiselect components to match the theme

[jfrer]

Previously there were the following issues:

• 2/3 of the dropdown components still matched the old theme.
• The document (GT) multiselect was still using the default multiselect, not the wrapper with a more accessible "select all" label.
• The hover effect of the default styling applied a border color that matched the border color without hover, so the border color remained unchanged on hover.

This PR resolves these problems by removing unstyled mode for all dropdowns, using the multiselect wrapper and changing the border color on hover to a more visible color.