refactor(css): add styles targeting SVG button/modal icons (#1464)

* refactor(css): add global classes for common icon types

* refactor(css): target child SVGs instead of creating new icon classes

* fix: fix ButtonWithDropdown style class spacing

src/components/RequestModal/SearchByNameModal/index.tsx

@@ -52,7 +52,7 @@ const SearchByNameModal: React.FC<SearchByNameModalProps> = ({
       okText={intl.formatMessage(globalMessages.next)}
       okDisabled={!tvdbId}
       okButtonType="primary"
-      iconSvg={<DownloadIcon className="w-6 h-6" />}
+      iconSvg={<DownloadIcon />}
     >
       <Alert
         title={intl.formatMessage(messages.notvdbiddescription)}