fix(Editor): bad request on empty resize + previous results not erased on language change

MSIS-2653

Author: steven.roulleau

examples/v4/rest/rest_text_iink.html

@@ -79,6 +79,7 @@
     const configuration = editorElement.editor.configuration;
     //The path to the language depend of the version of API you are using.
     configuration.recognitionParams.iink.lang = e.target.value;
+    resultElement.innerHTML = '';
   });
 
   undoElement.addEventListener('click', () => {

src/recognizer/rest/iinkRestRecognizer.js

@@ -217,5 +217,7 @@ export function convert (recognizerContext, model) {
  * @param {Model} model Current model
  */
 export function resize (recognizerContext, model) {
-  export_(recognizerContext, model)
+  if (model.strokeGroups.length) {
+    export_(recognizerContext, model)
+  }
 }