Change raw status code range check in MockClientHttpResponse

This commit changes the raw status code check to allow for all three
digit numbers, not just those between 100 and 600.

See gh-23599

spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpResponse.java

@@ -64,7 +64,7 @@ public class MockClientHttpResponse implements ClientHttpResponse {
 	}
 
 	public MockClientHttpResponse(int status) {
-		Assert.isTrue(status >= 100 && status < 600, "Status must be between 1xx and 5xx");
+		Assert.isTrue(status > 99 && status < 1000, "Status must be between 100 and 999");
 		this.status = status;
 	}