fix(ui,types): Add Metadata form for collection (#11300)

**What**
- Adds missing Metadata form for collections
- Fixes type of metadata in update payload
- Fixes an issue where deleting the last row of a metadata form would prevent adding new ones.

Resolves SUP-784

.changeset/blue-files-work.md

@@ -0,0 +1,6 @@
+---
+"@medusajs/dashboard": patch
+"@medusajs/types": patch
+---
+
+fix(ui,types): Add Metadata form for collection

packages/admin/dashboard/src/components/forms/metadata-form/metadata-form.tsx

@@ -113,6 +113,15 @@ const InnerForm = <TRes,>({
 
   function deleteRow(index: number) {
     remove(index)
+
+    // If the last row is deleted, add a new blank row
+    if (fields.length === 1) {
+      insert(0, {
+        key: "",
+        value: "",
+        disabled: false,
+      })
+    }
   }
 
   function insertRow(index: number, position: "above" | "below") {

packages/admin/dashboard/src/providers/router-provider/route-map.tsx

@@ -520,6 +520,11 @@ export const RouteMap: RouteObject[] = [
                         "../../routes/collections/collection-add-products"
                       ),
                   },
+                  {
+                    path: "metadata/edit",
+                    lazy: () =>
+                      import("../../routes/collections/collection-metadata"),
+                  },
                 ],
               },
             ],

packages/admin/dashboard/src/routes/collections/collection-metadata/collection-metadata.tsx

@@ -0,0 +1,26 @@
+import { useParams } from "react-router-dom"
+import { MetadataForm } from "../../../components/forms/metadata-form/metadata-form"
+import { useCollection, useUpdateCollection } from "../../../hooks/api"
+
+export const CollectionMetadata = () => {
+  const { id } = useParams()
+
+  const { collection, isPending, isError, error } = useCollection(id!)
+
+  const { mutateAsync, isPending: isMutating } = useUpdateCollection(
+    collection?.id!
+  )
+
+  if (isError) {
+    throw error
+  }
+
+  return (
+    <MetadataForm
+      metadata={collection?.metadata}
+      hook={mutateAsync}
+      isPending={isPending}
+      isMutating={isMutating}
+    />
+  )
+}

packages/admin/dashboard/src/routes/collections/collection-metadata/index.ts

@@ -0,0 +1 @@
+export { CollectionMetadata as Component } from "./collection-metadata"

packages/core/types/src/http/collection/admin/payloads.ts

@@ -25,7 +25,7 @@ export interface AdminUpdateCollection {
   /**
    * Key-value pairs of custom data.
    */
-  metadata?: Record<string, any>
+  metadata?: Record<string, any> | null
 }
 
 export interface AdminUpdateCollectionProducts {