fix: fix incoming nfts on new account

[MarkNerdi996]

Summary

If a new account is created, the nft store doesnt include a list for this account. Therefore we need to check if no list exists, and potentially create an empty one before adding elements to it

Changelog

- add empty list to NFT store if account gets created

Relevant Issues

Closes #5490

Testing

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[kraftjs]

Tested with minting and receiving NFTs. LGTM!