Deduplicate Thunderbird upgrade commands - just include install cmds instead

thunderbird.xml

@@ -23,10 +23,7 @@
     <exit code="128" />
   </upgrade>
 
-  <upgrade cmd='"%software%\thunderbird\Thunderbird Setup %version%.exe" -ms' />
-  <upgrade cmd='cmd /c copy "%software%\thunderbird\chemistry-prefs.js-%prefsversion%" "%programfileswpkg%\mozilla thunderbird\defaults\pref\chemistry-prefs.js" '/> 
-  <upgrade cmd='cmd /c copy "%software%\thunderbird\cam.ac.uk.xml" "%programfileswpkg%\mozilla thunderbird\isp\cam.ac.uk.xml" '/>
-  <upgrade cmd='%software%\wpkg\tools\copydir.cmd "%software%\thunderbird\dictionaries" "%programfileswpkg%\mozilla thunderbird\dictionaries"' /> 
+  <upgrade include='install' />
 
   <remove cmd='taskkill /F /IM thunderbird.exe'>
     <exit code="0" />