fix(FormSelect): fix props not being defined (#6106)

* change HTMLAttributes to SelectHTMLAttributes

* Omit size from interface since we use string instead of number to fix compile error

src/FormSelect.tsx

@@ -8,7 +8,7 @@ import FormContext from './FormContext';
 
 export interface FormSelectProps
   extends BsPrefixOnlyProps,
-    React.HTMLAttributes<HTMLSelectElement> {
+    Omit<React.SelectHTMLAttributes<HTMLSelectElement>, 'size'> {
   htmlSize?: number;
   size?: 'sm' | 'lg';
   isValid?: boolean;