[#86] Fixed the case when an exception is thrown for XML processing

accurest-core/src/main/groovy/io/codearte/accurest/util/ContentUtils.groovy

@@ -51,12 +51,19 @@ class ContentUtils {
 				return extractValueForXML(bodyAsValue, valueProvider)
 			} catch (Exception exception) {
 				log.debug("No content type provided and failed to parse as XML - returning the value back to the user", exception)
-				return bodyAsValue
+				return extractValueForGString(bodyAsValue, valueProvider)
 			}
 		}
 
 	}
 
+	private static GStringImpl extractValueForGString(GString bodyAsValue, Closure valueProvider) {
+		return new GStringImpl(
+				bodyAsValue.values.collect { it instanceof DslProperty ? valueProvider(it) : it } as String[],
+				bodyAsValue.strings.clone() as String[]
+		)
+	}
+
 	public static Object extractValue(GString bodyAsValue, Closure valueProvider) {
 		return extractValue(bodyAsValue, ContentType.UNKNOWN, valueProvider)
 	}