pindexer: insights: correctly handle Arb and Fees

[cronokirby]

Previously, these were being added to the supply, instead of subtracted.

This causes the supply in the insights dashboard to be slightly inflated.

Testing

To test, run pindexer and compare the following queries:

SELECT (
  SELECT SUM(um) as staked_um
    FROM (
      SELECT * FROM supply_validators
    ) validators
    LEFT JOIN LATERAL (
      SELECT um
      FROM supply_total_staked
      WHERE validator_id = id
      ORDER BY height DESC
      LIMIT 1
    ) staked_lateral ON TRUE)
+ um + auction + dex FROM supply_total_unstaked ORDER BY height DESC LIMIT 1;

SELECT total FROM insights_supply ORDER BY height DESC LIMIT 1;

Checklist before requesting a review

• I have added guiding text to explain how a reviewer should test these changes.

• If this code contains consensus-breaking changes, I have added the "consensus-breaking" label. Otherwise, I declare my belief that there are not consensus-breaking changes, for the following reason:

  Pindexer only

[cronokirby]

Not sufficient to fix the discrepancy ; further investigation required.