We need to test the error propagation behavior when chunk migration fails due to ingress operation rate limiter rejection. We should cover both the budget exhaustion and retry cap scenarios.

Given NetworkInterfaceTL-Sharding-Fixed was added to the IRRL exemption list, chunk migration should succeed even when the rate limiter is aggressively configured. The test asserts that moveChunk succeeds with defaultClientMaxRetryAttempts: 0 and a near-zero token rate, confirming that all migration sub-paths are correctly covered by the exemption list:

• DDL dispatch (_shardsvrMoveRange) from mongos → donor: Sharding-Fixed → exempt
• Batch fetch (_migrateClone) from recipient → donor: Sharding-Fixed executor → exempt
• Batch inserts on recipient: internal client (isProcessInternalClient() = true) → exempt

This approach was confirmed by Vojislav. See also SERVER-127632 for the analogous sharded-transaction commit exemption test as a reference for this pattern.