fix: resolve duplicate shortName for ONFA Chain and add icon to Mainnet

[mrchipdev]

Summary

This PR fixes issues with the ONFA Chain entries:

1. Fix duplicate shortName (breaking validation)

• eip155-12082025.json (Mainnet) and eip155-8691942025.json (Testnet) both used "shortName": "onfachain", which violates the unique shortName requirement.
• Changed Testnet's shortName from "onfachain" to "onfachain-testnet" to resolve the conflict.

2. Add missing icon field to Mainnet

• Added "icon": "onfachain" to eip155-12082025.json to reference the existing icon definition in _data/icons/onfachain.json.

Files Changed

• _data/chains/eip155-8691942025.json — updated shortName to "onfachain-testnet"
• _data/chains/eip155-12082025.json — added "icon": "onfachain"

[github-actions]

You successfully submitted a PR! Due to the amount of PRs coming in: we will only look at PRs that the CI is happy with. We can also not hold your hand getting the CI green - just look how others that where merged did it and RTFM. So as long as there is any CI check that reports an error - no human will look at this. You might be able to ask for some support after supporting the project - e.g. by sending funds to lists.eth. When you fixed things after a requested change - then you also need to (re-)request a review.

[ligi]

Resolve conflicts

[ligi]

also:

eip155-12082025.json (Mainnet) and eip155-8691942025.json (Testnet) both used "shortName": "onfachain", which violates the unique shortName requirement.

just checked this - it is not the case and I would be really surprised as the CI would not allow to merge this