Update bug_report.yaml (#10661)

Author: RDMacLachlan

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -37,7 +37,7 @@ body:
       options:
         - "WinUI 3 - Windows App SDK 1.7.3: 1.7.250606001"
         - "WinUI 3 - Windows App SDK 1.7 Preview 1: 1.7.250208002-preview1"
-        - "WinUI 3 - Windows App SDK 1.8 Experimental 1: 1.8.250515001-experimental2"
+        - "WinUI 3 - Windows App SDK 1.8 Experimental 4: 1.8.250702007-experimental4"
         - "WinUI 2 - Microsoft.UI.Xaml 2.8.2"
   - type: dropdown
     attributes: