Clean up old files when installing on Windows (#5645)

* app: always clean up install dir; force close applications

* remove wildcard

* revert `CloseApplications`

* whitespace

* update `LOCALAPPDATA` var

app/ollama.iss

@@ -127,6 +127,9 @@ Type: filesandordirs; Name: "{%USERPROFILE}\.ollama\models"
 Type: filesandordirs; Name: "{%USERPROFILE}\.ollama\history"
 ; NOTE: if the user has a custom OLLAMA_MODELS it will be preserved
 
+[InstallDelete]
+Type: filesandordirs; Name: "{%LOCALAPPDATA}\Programs\Ollama"
+
 [Messages]
 WizardReady=Ollama Windows Preview
 ReadyLabel1=%nLet's get you up and running with your own large language models.