fix: remove tabIndex={-1} from clear button to make it keyboard accessible

The clear button had tabIndex={-1} which made it unreachable via keyboard
navigation, violating WCAG 2.1 success criteria 2.1.1 and 2.1.3.

This change makes the clear button focusable so keyboard users can
access and operate this functionality.

Fixes ant-design/ant-design#57378

Author: cyphercodes

src/BaseInput.tsx

@@ -88,7 +88,6 @@ const BaseInput = React.forwardRef<HolderRef, BaseInputProps>((props, ref) => {
       clearIcon = (
         <button
           type="button"
-          tabIndex={-1}
           onClick={(event) => {
             handleReset?.(event);
             onClear?.();