* Metaplex NFTs: Added external URL button to explorer
- moved fetching MetadataJSON from URI to MetaplexNFTHeader
- checked if external_url exists in MetadataJSON
- rendered a button to link to the external url if it exists
* cleanup unused import
* fixed code formatting
* Changed NFT website button to overview section field and Moved NFT URI fetch logic to accounts provider.
* removed unused CSS
* Update TokenAccountSection.tsx
* fixed formatting and 1 other error