Update removeSupportAllNFTs method of NFT module

[Incede]

Description

The removeSupportAllNFTs method of the NFT module may not remove support of all NFTs if the ALL_SUPPORTED_NFTS_KEY is present. The getAll function will never return the ALL_SUPPORTED_NFTS_KEY key because it iterates over all keys of size LENGTH_CHAIN_ID but ALL_SUPPORTED_NFTS_KEY is the empty string.

Acceptance Criteria

• In the removeSupportAllNFTs function, also remove the ALL_SUPPORTED_NFTS_KEY key
• Add unit test

Additional Information

release/6.1.0