Prevent auto restart after LibreOffice install

Commit 815c9aa (PR microsoft#1210) fixed this for the 6.4 version manifest file.

This change adds the `/qn /norestart` to the 7.1 manifest files where it is missing, resulting in an unprompted PC restart on upgrade.

Fixes microsoft#1154

manifests/l/LibreOffice/LibreOffice/7.1.3.2/LibreOffice.LibreOffice.yaml

@@ -45,6 +45,9 @@ License: Mozilla Public License Version 2.0
 LicenseUrl: https://www.libreoffice.org/about-us/licenses
 PackageVersion: 7.1.3.2
 InstallerType: msi
+InstallerSwitches:
+  Silent: /qn /norestart
+  SilentWithProgress: /qn /norestart
 Installers:
 - Architecture: x64
   InstallerType: msi