[Blockscout] Kudos NFT Metadata includes invalid link

**Describe the bug**
There is an issue in Kudos ERC-721 metadata: "external_url" field gives 404.
For example, [this](https://blockscout.com/xdai/mainnet/token/0x74e596525C63393f42C76987b6A66F4e52733efa/instance/126461/metadata) NFT meta
gives invalid url
https://gitcoin.co/kudos/0x74e596525C63393f42C76987b6A66F4e52733efa/126385 - 404

**To Reproduce**
1. Open any Kudos token instance on BlockScout. For example, this [one](https://blockscout.com/xdai/mainnet/token/0x74e596525c63393f42c76987b6a66f4e52733efa/instance/126390/token-transfers).
2. View metadata, "external_url" field. Link is invalid.
3. "View in app" button does not work as it takes address from meta.

**Expected behavior**
- "external_url" should provide a valid link to Kudos page.
- Correct link: https://gitcoin.co/kudos/12384770/
- Token instance number is not needed in the URL, kudos id should be included, not token instance id.

**Screenshots**
https://prnt.sc/1ucidsp

**Additional context**
This bug is submitted by BlockScout team