Add 'advisor' to autorevert_events_v2 action enum (#7878)

## Summary

- Adds `'advisor' = 3` to the `action` Enum8 column in
`misc.autorevert_events_v2`

The autorevert AI advisor lambda ([pytorch/pytorch PR
#177404](pytorch/pytorch#177404)) writes
`action='advisor'` when logging dispatch events to ClickHouse. However,
the table's Enum8 only accepted `none`, `restart`, `revert` — causing
ClickHouse to silently store advisor rows as `action='none'`.

This broke `prior_advisor_exists()` and `advisor_count_for_commit()`
which query `WHERE action = 'advisor'` — they always returned false/0,
so the lambda re-dispatched the advisor workflow for the same (commit,
signal) every ~5 minutes indefinitely.

Already applied live:
```sql
ALTER TABLE misc.autorevert_events_v2
  MODIFY COLUMN `action` Enum8('none' = 0, 'restart' = 1, 'revert' = 2, 'advisor' = 3)
```

## Test plan
- [x] Verify schema file matches expected Enum values
- [x] Apply ALTER TABLE on the live ClickHouse instance
- [ ] Confirm subsequent advisor dispatches create rows with
`action='advisor'`
- [ ] Confirm `prior_advisor_exists()` returns true after first
dispatch, preventing duplicates

Author: izaitsevfb

clickhouse_db_schema/misc.autorevert_events_v2/schema.sql

@@ -2,7 +2,7 @@ CREATE TABLE misc.autorevert_events_v2
 (
     `ts` DateTime DEFAULT now(),
     `repo` LowCardinality(String) DEFAULT 'pytorch/pytorch',
-    `action` Enum8('none' = 0, 'restart' = 1, 'revert' = 2),
+    `action` Enum8('none' = 0, 'restart' = 1, 'revert' = 2, 'advisor' = 3),
     `commit_sha` FixedString(40),
     `workflows` Array(String),
     `source_signal_keys` Array(String),