[Update Request]: Microsoft.WindowsAppRuntime.1.8 1.8.11 (1.8.260804001)

### What type of update are you requesting?

A new version of an existing package

### Current Package Identifier

Microsoft.WindowsAppRuntime.1.8

### Package Version

1.8.11 (1.8.260804001)

### Please describe the changes you would like to see

There is a new release (1.8.11 (1.8.260804001)) available.
Download Page URL: https://learn.microsoft.com/en-us/windows/apps/windows-app-sdk/downloads-archive
Installer (x64): https://aka.ms/windowsappsdk/1.8/1.8.260804001/windowsappruntimeinstall-x64.exe
Installer (x86): https://aka.ms/windowsappsdk/1.8/1.8.260804001/windowsappruntimeinstall-x86.exe
Installer (arm64): https://aka.ms/windowsappsdk/1.8/1.8.260804001/windowsappruntimeinstall-arm64.exe

Locate the existing Microsoft.WindowsAppRuntime.1.8 package manifest in the winget-pkgs repository and compare its current version and installer URLs with the release details in this issue. Update the manifest for version 1.8.11 (1.8.260804001), preserve the listed architectures, and verify that the package manifest passes repository validation.

Written by the indexing model from the issue text.