[Ubuntu] Migrate tests for Android to Pester (#2313)

* Add Pester tests for Android on Ubuntu

* Minor fix

* Move Get-AndroidPackages to common helpers

* Minor fix

* Delete Android test name for invoke_tests script

images/linux/scripts/helpers/Common.Helpers.psm1

@@ -32,4 +32,26 @@ function Test-IsUbuntu20 {
 function Get-ToolsetContent {
     $toolset = Join-Path $env:INSTALLER_SCRIPT_FOLDER "toolset.json"
     Get-Content $toolset -Raw | ConvertFrom-Json
+}
+
+function Get-ToolsetValue {
+    param (
+        [Parameter(Mandatory = $true)]
+        [string] $KeyPath
+    )
+
+    $jsonNode = Get-ToolsetContent
+
+    $pathParts = $KeyPath.Split(".")
+    # try to walk through all arguments consequentially to resolve specific json node
+    $pathParts | ForEach-Object {
+        $jsonNode = $jsonNode.$_
+    }
+    return $jsonNode
+}
+
+function Get-AndroidPackages {
+    $androidSDKManagerPath = "/usr/local/lib/android/sdk/tools/bin/sdkmanager"
+    $androidPackages = & $androidSDKManagerPath --list --verbose
+    return $androidPackages
 }