Fix upload button media not working (#2354)

* Fix upload button media not working

* format

* Update mint-form.tsx

Signed-off-by: Jonas Daniels <[email protected]>

---------

Signed-off-by: Jonas Daniels <[email protected]>
Co-authored-by: Jonas Daniels <[email protected]>

Author: nachoiacovino

contract-ui/tabs/nfts/components/mint-form.tsx

@@ -416,7 +416,7 @@ export const NFTMintForm: React.FC<NFTMintForm> = ({
                 maxContainerWidth={"200px"}
                 value={mediaFileUrl}
                 showUploadButton
-                showPreview={!!mediaFileUrl}
+                showPreview={nft?.metadata ? !!mediaFileUrl : true}
                 setValue={setFile}
                 border="1px solid"
                 borderColor="gray.200"