Allow setting a timeout for clicking download buttons

scripts/Common/Scripts/BrowserAutomation.ps1

@@ -127,12 +127,16 @@ $null = New-Module {
 
         .PARAMETER OutDir
         The directory to download the file to.
+
+        .PARAMETER Timeout
+        The number of seconds to wait before clicking the download button.
     #>
     function Start-BrowserDownload {
         param(
             [string] $URL,
             [string] $ButtonSelector,
-            [string] $OutDir = $null
+            [string] $OutDir = $null,
+            [double] $Timeout = 0
         )
 
         Start-CustomBrowserDownload @PSBoundParameters -Action {
@@ -153,8 +157,12 @@ $null = New-Module {
                 }
             }
 
+            if ($Timeout -gt 0) {
+                Start-Sleep $Timeout;
+            }
+
             if ($element) {
-                $Browser.FindElement([OpenQA.Selenium.By]::CssSelector($ButtonSelector)).Click();
+                $Browser.FindElement($selector).Click();
             } else {
                 Write-Error "Unable to find download button!";
             }