used mdi icons instead of font awesome

packages/web/src/modals/ErrorMessageModal.js

@@ -25,7 +25,7 @@ export default function ErrorMessageModal({ modalState, title = 'Error', message
       <ModalContent>
         <Wrapper>
           <IconWrapper>
-            <FontIcon icon="fas fa-times-circle red" />
+            <span className="mdi mdi-close-circle color-red" />
           </IconWrapper>
           {message}
         </Wrapper>

packages/web/src/modals/ModalHeader.js

@@ -23,7 +23,7 @@ export default function ModalHeader({ children, modalState }) {
     <Wrapper>
       <div>{children}</div>
       <CloseWrapper onClick={modalState.close}>
-        <i className="fas fa-times" />
+        <span className="mdi mdi-close" />
       </CloseWrapper>
     </Wrapper>
   );