Escape keys when exporting to properties file

Author: Christine WANJAU

src/azure-cli/azure/cli/command_modules/appconfig/_kv_export_helpers.py

@@ -125,7 +125,8 @@ def __write_kv_and_features_to_file(
                     exported_keyvalues, fp, sort_keys=False, width=float("inf")
                 )
             elif format_ == "properties":
-                javaproperties.dump(exported_keyvalues, fp)
+                for key, value in exported_keyvalues.items():
+                    fp.write('{}={}\n'.format(javaproperties.escape(key), value))
     except Exception as exception:
         raise FileOperationError(
             "Failed to export key-values to file. " + str(exception)