allow using --check on win_iis_webapppool module (#50528)

* allow using --check on win_iis_webapppool module

* Added changelog and slight logic tweak

* Fix typo in changelog fragment

changelogs/fragments/win_iis_webapppool-check-mode.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+- win_iis_webapppool - Do not try and set attributes in check mode when the pool did not exist

lib/ansible/modules/windows/win_iis_webapppool.ps1

@@ -201,6 +201,8 @@ if ($state -eq "absent") {
         }
     }
 
+    # Cannot run the below in check mode if the pool did not always exist
+    if ($pool) {
         # Modify pool based on parameters
         foreach ($attribute in $attributes.GetEnumerator()) {
             $attribute_key = $attribute.Name
@@ -269,6 +271,7 @@ if ($state -eq "absent") {
                 $result.changed = $true
             }
         }
+    }
 }
 
 # Get all the current attributes for the pool