Use system properties when constructing Apache HttpClient

See gh-38591

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/client/ClientHttpRequestFactories.java

@@ -190,7 +190,8 @@ private static HttpClient createHttpClient(Duration readTimeout, SslBundle sslBu
 						options.getEnabledProtocols(), options.getCiphers(), new DefaultHostnameVerifier());
 				connectionManagerBuilder.setSSLSocketFactory(socketFactory);
 			}
-			PoolingHttpClientConnectionManager connectionManager = connectionManagerBuilder.build();
+			PoolingHttpClientConnectionManager connectionManager = connectionManagerBuilder.useSystemProperties()
+				.build();
 			return HttpClientBuilder.create().useSystemProperties().setConnectionManager(connectionManager).build();
 		}