Move script checking Appium server status to separate file (#38692)

Summary:
This PR is small cleanup in `.circleci/config.yml` file. Request here: #36267 (comment)

## Changelog:
[INTERNAL] [CHANGED] - move script checking Appium server status to separate file

Pull Request resolved: #38692

Test Plan: CI Green ✅

Reviewed By: NickGerleman

Differential Revision: D47926222

Pulled By: ryancat

fbshipit-source-id: eeff338ca018549762dce46a744b80f659b4bd5d

Author: szymonrybczak

.circleci/config.yml

@@ -785,11 +785,7 @@ jobs:
           command: mv /tmp/e2e/Build/Products/Debug-iphonesimulator/RNTester.app packages/rn-tester-e2e/apps/rn-tester.app
       - run:
           name: Check Appium server status
-          command: |
-            if ! nc -z 127.0.0.1 4723; then
-              echo Could not find Appium server!
-              exit 1
-            fi
+          command: scripts/circleci/check_appium_server_status.sh
       - run:
           name: Run E2E tests
           command: |

scripts/circleci/check_appium_server_status.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+# This script checks if Appium server is running on default port (which is 4723).
+if ! nc -z 127.0.0.1 4723; then
+  echo Could not find Appium server.
+  exit 1
+fi