Update Appium.js - Issue #4047 - bstack:options'Prefix (#4053)

Author: mojtabaalavi

lib/helper/Appium.js

@@ -276,7 +276,7 @@ class Appium extends Webdriver {
     const _convertedCaps = {};
     for (const [key, value] of Object.entries(capabilities)) {
       if (!key.startsWith(vendorPrefix.appium)) {
-        if (key !== 'platformName') {
+        if (key !== 'platformName' && key !== 'bstack:options') {
           _convertedCaps[`${vendorPrefix.appium}:${key}`] = value;
         } else {
           _convertedCaps[`${key}`] = value;