BEDS-1165 / fix missed el rewards in group summary for a period

[sasha-bitfly]

Missed el rewards is constant and the same for a period last_1h, all_time

https://v2-staging-holesky.beaconcha.in/api/i/validator-dashboards/v-80d7edaa-74fb-4129-a41e-7700756961cf/groups/-1/summary?period=last_1h

https://v2-staging-holesky.beaconcha.in/api/i/validator-dashboards/v-80d7edaa-74fb-4129-a41e-7700756961cf/groups/-1/summary?period=all_time

For both API calls:

"missed_rewards": {
  "proposer_rewards": {
    "el": "33672441519334000000"

clickhouse table was picked for all_time period always, the fix is to pick clickhouse table name depending on a period