Fix: Nft preview unavailable box

[tuliomir]

In the "Token Details" screen, in the cases where the custom token has a preview, the screen was misaligned. See screenshots below

Acceptance Criteria

• The current UI should correctly exhibit the screen when it has a preview
• The new UI should correctly exhibit the "Preview Unavailable" message

Notes

It was not possible to test the correct preview of an NFT for now, as the Explorer Service / Wallet Service are not properly validating all new NFTs created at the time. So, the "content overwrite" feature of Chromium was used to simulate the NFT registration, but without any pictures.

Current UI , before the fix

Current UI , after the fix

New UI, before the fix

New UI, after the fix

Security Checklist

• Make sure you do not include new dependencies in the project unless strictly necessary and do not include dev-dependencies as production ones. More dependencies increase the possibility of one of them being hijacked and affecting us.