chore(windows): style the MSI installer (#4990)

Closes #4919 

![image](https://github.com/firezone/firezone/assets/13400041/455bd444-3b75-4bfb-8cc0-afdcd29c55de)

![image](https://github.com/firezone/firezone/assets/13400041/b166fb9a-d7bc-4ac8-8ade-99cebfc7b7a5)

![image](https://github.com/firezone/firezone/assets/13400041/27eff651-08a4-4185-93cc-e1e544595ad8)

rust/gui-client/src-tauri/tauri.conf.json

@@ -38,7 +38,9 @@
       "shortDescription": "Firezone",
       "windows": {
         "wix": {
+          "bannerPath": "./win_files/banner.png",
           "componentRefs": ["FirezoneClientIpcService"],
+          "dialogImagePath": "./win_files/install_dialog.png",
           "fragmentPaths": ["./win_files/service.wxs"],
           "template": "./win_files/main.wxs"
         }