fix: removes nested array field configs from array value (#3549)

* fix: array controls 'addBelow' was adding above

test/fields/collections/Array/components/AddCustomBlocks/index.tsx

@@ -10,8 +10,6 @@ export const AddCustomBlocks: React.FC = () => {
   const { addFieldRow, replaceFieldRow } = useForm()
   const { value } = useField({ path: 'customBlocks' })
 
-  const nextIndex = Array.isArray(value) ? value.length : 0
-
   return (
     <div className={baseClass}>
       <div className={`${baseClass}__blocks-grid`}>
@@ -21,7 +19,6 @@ export const AddCustomBlocks: React.FC = () => {
             addFieldRow({
               data: { block1Title: 'Block 1: Prefilled Title', blockType: 'block-1' },
               path: 'customBlocks',
-              rowIndex: nextIndex,
             })
           }
           type="button"
@@ -35,7 +32,6 @@ export const AddCustomBlocks: React.FC = () => {
             addFieldRow({
               data: { block2Title: 'Block 2: Prefilled Title', blockType: 'block-2' },
               path: 'customBlocks',
-              rowIndex: nextIndex,
             })
           }
           type="button"
@@ -51,12 +47,12 @@ export const AddCustomBlocks: React.FC = () => {
             replaceFieldRow({
               data: { block1Title: 'REPLACED BLOCK', blockType: 'block-1' },
               path: 'customBlocks',
-              rowIndex: nextIndex - 1,
+              rowIndex: (Array.isArray(value) ? value.length : 0) - 1,
             })
           }
           type="button"
         >
-          Replace Block {nextIndex}
+          Replace Block {Array.isArray(value) ? value.length : 0}
         </button>
       </div>
     </div>