Improve error displayed when trying to transfer SIP010 token without gas token balance

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When a user tries to send a SIP010 transfer without STX balance they should be warned they need STX to cover gas fees. They should be earlier in the process (see reproduction steps, I would say at 6, with a meaningful error; "not enough STX to cover gas fees").

Alternatively, especially for sBTC we could consider:
Or their transaction should get sponsored automatically; then it should be displayed on the review page (step 7), including the cost of the sponsored transaction. Or we can direct users to use swap, to swap some of their SIP010 token to STX to cover future gas fees. There sponsoring is already supported.

Reproduction steps

1. Create wallet account with some sBTC and no gas asset
2. Click send
3. select sBTC
4. add amount
5. add recipient's address
6. click "continue"
7. click "confirm and send transaction"
8. See error:

[linear]

LEA-2377 Improve error displayed when trying to transfer SIP010 token without gas token balance