Improve error reporting for CIS-2 tokens

[Radiokot]

Related: BRO-29

⚠ Before making any new changes to the CIS-2 management flow in CryptoX we should first have it re-designed to match the final requirements and to provide the same experience on both Android and iOS.

When looking for CIS-2 tokens and having some with corrupted/missing/invalid metadata or balance:

• Do not filter out problematic tokens;
• Show problematic tokens in the list with their error messages. In the worst case, it is just an image placeholder, token ID as a name and the error message;
• Do not allow selection of problematic tokens – hide the checkbox;
• Do the same when searching for a token by ID;
• Only if the contract has no tokens at all, do not switch to the tokens list and show "This contract has no tokens" message on the contract index input screen.