ComposeForm: convert buttons to ComposeFormButton component

app/soapbox/features/compose/components/compose_form_button.tsx

@@ -0,0 +1,34 @@
+import classNames from 'classnames';
+import React from 'react';
+
+import { IconButton } from 'soapbox/components/ui';
+
+interface IComposeFormButton {
+  icon: string,
+  title?: string,
+  active?: boolean,
+  disabled?: boolean,
+  onClick: () => void,
+}
+
+const ComposeFormButton: React.FC<IComposeFormButton> = ({
+  icon,
+  title,
+  active,
+  disabled,
+  onClick,
+}) => {
+  return (
+    <div>
+      <IconButton
+        className={classNames('text-gray-400 hover:text-gray-600', { 'text-gray-600': active })}
+        src={icon}
+        title={title}
+        disabled={disabled}
+        onClick={onClick}
+      />
+    </div>
+  );
+};
+
+export default ComposeFormButton;