check playht can fetch voices when adding new speech credential (#309)

* check playht can fetch voices when adding new speech credential

* wip

* wip

* wip

* wip

lib/routes/api/speech-credentials.js

@@ -743,7 +743,12 @@ router.get('/:sid/test', async(req, res) => {
           results.tts.status = 'ok';
           SpeechCredential.ttsTestResult(sid, true);
         } catch (err) {
-          results.tts = {status: 'fail', reason: err.message};
+          let reason = err.message;
+          // if error is from bent, let get the body
+          try {
+            reason = await err.text();
+          } catch {}
+          results.tts = {status: 'fail', reason};
           SpeechCredential.ttsTestResult(sid, false);
         }
       }