Disable macros in Viewer Mode

Prevents "This document contains macros" dialog on file open.

Change-Id: I92cbd6b5f919ccfa5812b4a90ec72ad4378d009a
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178273
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

unotools/source/config/securityoptions.cxx

@@ -205,7 +205,9 @@ void SetMacroSecurityLevel( sal_Int32 _nLevel )
 
 bool IsMacroDisabled()
 {
-    return comphelper::IsFuzzing() || officecfg::Office::Common::Security::Scripting::DisableMacrosExecution::get();
+    return comphelper::IsFuzzing()
+           || officecfg::Office::Common::Security::Scripting::DisableMacrosExecution::get()
+           || officecfg::Office::Common::Misc::ViewerAppMode::get();
 }
 
 std::vector< SvtSecurityOptions::Certificate > GetTrustedAuthors()