fix: retain Toolbar min-height (#261)

Author: zzmp

src/components/Swap/Toolbar/Caption.tsx

@@ -66,7 +66,7 @@ export function Error() {
   return <Caption caption={<Trans>Error fetching trade</Trans>} />
 }
 
-export function Empty() {
+export function MissingInputs() {
   return <Caption icon={Info} caption={<Trans>Enter an amount</Trans>} />
 }
 

src/components/Swap/Toolbar/index.tsx

@@ -13,6 +13,7 @@ const ToolbarRow = styled(Row)`
   background-color: ${({ theme }) => theme.module};
   border-bottom-left-radius: ${({ theme }) => theme.borderRadius - 0.25}em;
   border-bottom-right-radius: ${({ theme }) => theme.borderRadius - 0.25}em;
+  min-height: 44px;
   padding: 14px 16px;
 `
 
@@ -68,7 +69,7 @@ export default memo(function Toolbar() {
       }
     }
 
-    return <Caption.Empty />
+    return <Caption.MissingInputs />
   }, [
     error,
     state,