修复字符集bug

backend/src/main/java/io/metersphere/api/jmeter/APIBackendListenerClient.java

@@ -126,7 +126,7 @@ public class APIBackendListenerClient extends AbstractBackendListenerClient impl
         }
 
         ResponseResult responseResult = requestResult.getResponseResult();
-        responseResult.setBody(new String(result.getResponseData(), StandardCharsets.UTF_8));
+        responseResult.setBody(result.getResponseDataAsString());
         responseResult.setHeaders(result.getResponseHeaders());
         responseResult.setLatency(result.getLatency());
         responseResult.setResponseCode(result.getResponseCode());

backend/src/main/resources/jmeter/bin/jmeter.properties

@@ -1081,7 +1081,7 @@ csvdataset.file.encoding_list=UTF-8|UTF-16|ISO-8859-15|US-ASCII
 #httpsampler.user_defined_methods=VERSION-CONTROL,REPORT,CHECKOUT,CHECKIN,UNCHECKOUT,MKWORKSPACE,UPDATE,LABEL,MERGE,BASELINE-CONTROL,MKACTIVITY
 
 # The encoding to be used if none is provided (default ISO-8859-1)
-#sampleresult.default.encoding=ISO-8859-1
+sampleresult.default.encoding=UTF-8
 
 # CookieManager behaviour - should cookies with null/empty values be deleted?
 # Default is true. Use false to revert to original behaviour