fix(plugin-seo): thread allowCreate to meta image component (#12624)

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Fixes #

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### What?
This PR fixes an issue with `plugin-seo` where the `MetaImageComponent`
would not allow creating a new upload document from the field.

### Why?
To allow users to upload new media documents for use as a meta image.

### How?
Threads `allowCreate` through to the underlying upload input.

Fixes #12616

Before:

![image](https://github.com/user-attachments/assets/44ec32c7-1912-4fc3-9b8a-f5deb167320b)

After:

![image](https://github.com/user-attachments/assets/0dba1f75-78b6-4472-af38-6178f2ab26ea)

packages/plugin-seo/src/fields/MetaImage/MetaImageComponent.tsx

@@ -29,7 +29,7 @@ type MetaImageProps = {
 
 export const MetaImageComponent: React.FC<MetaImageProps> = (props) => {
   const {
-    field: { label, localized, relationTo, required },
+    field: { admin: { allowCreate } = {}, label, localized, relationTo, required },
     hasGenerateImageFn,
     readOnly,
   } = props
@@ -175,6 +175,7 @@ export const MetaImageComponent: React.FC<MetaImageProps> = (props) => {
         }}
       >
         <UploadInput
+          allowCreate={allowCreate !== false}
           api={api}
           collection={collection}
           Error={Error}