Fix TestConcurrentHealthCheckAndHeartbeat assertion (#4780)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Bug Fixes**
	- Enhanced error handling in tests for concurrent heartbeats.
- Improved assertions and validations for expected states and error
messages.

- **New Features**
- Added new test cases for shutdown notice handling and resource
management.
	- Included concurrency tests for simultaneous operations.
	- Verified lifecycle management with checks for idempotency.
- Ensured state persistence during manager stop and context
cancellation.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

pkg/orchestrator/nodes/manager_test.go

@@ -485,7 +485,7 @@ func (s *NodeManagerTestSuite) TestConcurrentHealthCheckAndHeartbeat() {
 			})
 			// Either succeed or fail with concurrent update error
 			if err != nil {
-				assert.Contains(s.T(), err.Error(), "concurrent update conflict")
+				s.True(bacerrors.IsErrorWithCode(err, nodes.ConcurrentUpdate))
 			}
 		}()
 	}