Expose "chunk produced / expected" values on the Nodes Page

[frol]

We currently display "block produced / expected" values on the Nodes Page for each validator, but with the recent changes to NEAR Protocol, there is also "chunk produced / expected" for each validation node, so we should display that as well.

validators API has those values exposed since the recent 1.23.1 release:

"current_validators": [
            {
                "account_id": "staked.poolv1.near",
                "public_key": "ed25519:3JBVXqenru2ErAM1kHQ8qfd29dCkURLd6JKrFgtmcDTZ",
                "is_slashed": false,
                "stake": "42541319589362938700262925035492",
                "shards": [
                    0,
                    1,
                    2,
                    3
                ],
                "num_produced_blocks": 890,
                "num_expected_blocks": 902,
                "num_produced_chunks": 3729,
                "num_expected_chunks": 3804
            },
            {
                "account_id": "astro-stakers.poolv1.near",
                "public_key": "ed25519:2nPSBCzjqikgwrqUMcuEVReJhmkC91eqJGPGqH9sZc28",
                "is_slashed": false,
                "stake": "20799077330701881034151674770434",
                "shards": [
                    0,
                    1,
                    2,
                    3
                ],
                "num_produced_blocks": 476,
                "num_expected_blocks": 476,
                "num_produced_chunks": 1828,
                "num_expected_chunks": 1841
            }

let's display online in percentage ("99.99%"), and then on hover show "produced 100/101 blocks, 50/51 chunks"