fix(bundler): blank taskbar icon on WiX update, closes #5631 (#5779)

.changes/blank-taskbar-icon-windows.md

@@ -0,0 +1,5 @@
+---
+"tauri-bundler": patch
+---
+
+Fixes blank taskbar icon on WiX updates.

tooling/bundler/src/bundle/windows/templates/main.wxs

@@ -30,9 +30,9 @@
         <Property Id="REINSTALLMODE" Value="amus" />
 
         {{#if allow_downgrades}}
-            <MajorUpgrade AllowDowngrades="yes" Schedule="afterInstallValidate" />
+            <MajorUpgrade Schedule="afterInstallInitialize" AllowDowngrades="yes" />
         {{else}}
-            <MajorUpgrade DowngradeErrorMessage="!(loc.DowngradeErrorMessage)" AllowSameVersionUpgrades="yes" />
+            <MajorUpgrade Schedule="afterInstallInitialize" DowngradeErrorMessage="!(loc.DowngradeErrorMessage)" AllowSameVersionUpgrades="yes" />
         {{/if}}
 
         <InstallExecuteSequence>