Add new response variable for interpreter

[NikitaSavik]

In order to support links in Summary response, we need to add such type of variable-

{ "summary_template": "Created {txn_list}", "summary_template_variables": { "txn_list": { "type": "external_link", "value": { "name": "Transactions", "link": "https://zksync.blockscout.com/batches/494573" } } } }

Summary should look like this - "Created Transactions"