Fix server property assignment in the umbrella driver (#10496)

lib/appium.js

@@ -227,6 +227,8 @@ class AppiumDriver extends BaseDriver {
         log.info(`Applying relaxed security to ${InnerDriver.name} as per server command line argument`);
         d.relaxedSecurityEnabled = true;
       }
+      // This assignment is required for correct web sockets functionality inside the driver
+      d.server = this.server;
       try {
         runningDriversData = await this.curSessionDataForDriver(InnerDriver);
       } catch (e) {