feat(android-setup): detect-adb-step dialog implementation (#2802)

* added the spinner to the detect-adb-step ui

* added a standalone scss file for android-setup styling. simplified detect-adb-step to just return the spinner and not call a method

src/electron/views/device-connect-view/components/android-setup/android-setup.scss

@@ -0,0 +1,5 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+.android-setup-spinner {
+    padding-top: 25%;
+}

src/electron/views/device-connect-view/components/android-setup/detect-adb-step.tsx

@@ -2,11 +2,22 @@
 // Licensed under the MIT License.
 import { NamedFC } from 'common/react/named-fc';
 import { CommonAndroidSetupStepProps } from 'electron/views/device-connect-view/components/android-setup/android-setup-types';
+import { Spinner, SpinnerSize } from 'office-ui-fabric-react';
 import * as React from 'react';
 
+import { androidSetupSpinner } from '../android-setup/android-setup.scss';
+
 export const DetectAdbStep = NamedFC<CommonAndroidSetupStepProps>(
     'DetectAdbStep',
     (props: CommonAndroidSetupStepProps) => {
-        return <>step: {props.androidSetupStoreData.currentStepId}</>;
+        return (
+            <Spinner
+                className={androidSetupSpinner}
+                size={SpinnerSize.large}
+                label="Loading..."
+                role="alert"
+                aria-live={props['aria-live']}
+            />
+        );
     },
 );

src/tests/unit/tests/electron/views/device-connect-view/components/android-setup/__snapshots__/detect-adb-step.test.tsx.snap

@@ -1,8 +1,10 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`DetectAdbStep renders 1`] = `
-<React.Fragment>
-  step: 
-  detect-adb
-</React.Fragment>
+<StyledSpinnerBase
+  className="androidSetupSpinner"
+  label="Loading..."
+  role="alert"
+  size={3}
+/>
 `;