fix(clickhouse): remove semicolon from migration comment

The testcontainers migration parser splits Up statements on ';',
including semicolons inside comments, which produced a comments-only
fragment rejected by ClickHouse as 'Empty query.'

Author: carderne

internal-packages/clickhouse/schema/038_add_task_events_inserted_at_index.sql

@@ -1,6 +1,6 @@
 -- +goose Up
 -- Source index supporting closed projector windows on newly written parts.
--- ADD INDEX only defines the index for new parts; existing parts are not materialized.
+-- ADD INDEX only defines the index for new parts and does not materialize existing parts.
 ALTER TABLE trigger_dev.task_events_v2
   ADD INDEX IF NOT EXISTS idx_inserted_at_projector inserted_at TYPE minmax GRANULARITY 1;