fix: replace border-gray-300 with a themable colour (#664)

Co-authored-by: Aman Harwara <amanharwara@protonmail.com>

app/assets/javascripts/components/DecoratedInput.tsx

@@ -31,7 +31,7 @@ export const DecoratedInput: FunctionalComponent<Props> = ({
     'rounded py-1.5 px-3 text-input my-1 h-8 flex flex-row items-center bg-contrast';
   const stateClasses = disabled
     ? 'no-border'
-    : 'border-solid border-1 border-gray-300';
+    : 'border-solid border-1 border-neutral';
   const classes = `${baseClasses} ${stateClasses} ${className}`;
 
   const inputBaseClasses = 'w-full no-border color-text focus:shadow-none bg-contrast';