feat(windows): apply update now give progress if download still in progress

When user now selects `Apply Update Now` and a download has not completed in the background there will be a pause while it downloads the install. This issue is to adding a visual indication, such as a progress bar

When this is implemented search for #13711 in UfrmMain.pas and update the DownloadRequired message to just say download requried. remove the extra message that "the update will be downloaded in the background."