v3.138.3

• Fixed panic risks in tracing callbacks by separating error and success paths in spans/metrics and by making internal pool trace types generic-safe.
• Fixed ydb.WithStatsMode* for database/sql silently dropping a previously registered stats callback when called more than once on the same context. Repeated calls now chain callbacks (they fire in registration order) and the effective stats mode is the most detailed one across the chain.

Full Changelog: v3.138.2...v3.138.3