Update SiteExtensions package version (#26972)

Author: wtgodbe

eng/Versions.props

@@ -208,7 +208,7 @@
     <!-- Packages from 2.1, 3.1, and 5.0 branches used for site extension build. -->
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension21PackageVersion>2.1.1</MicrosoftAspNetCoreAzureAppServicesSiteExtension21PackageVersion>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension22PackageVersion>2.2.0</MicrosoftAspNetCoreAzureAppServicesSiteExtension22PackageVersion>
-    <MicrosoftAspNetCoreAzureAppServicesSiteExtension31PackageVersion>3.1.8-servicing-20421-6</MicrosoftAspNetCoreAzureAppServicesSiteExtension31PackageVersion>
+    <MicrosoftAspNetCoreAzureAppServicesSiteExtension31PackageVersion>3.1.9-servicing-20473-9</MicrosoftAspNetCoreAzureAppServicesSiteExtension31PackageVersion>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension31x64PackageVersion>$(MicrosoftAspNetCoreAzureAppServicesSiteExtension31PackageVersion)</MicrosoftAspNetCoreAzureAppServicesSiteExtension31x64PackageVersion>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension31x86PackageVersion>$(MicrosoftAspNetCoreAzureAppServicesSiteExtension31PackageVersion)</MicrosoftAspNetCoreAzureAppServicesSiteExtension31x86PackageVersion>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension50PackageVersion>5.0.0-preview-7-20365-19</MicrosoftAspNetCoreAzureAppServicesSiteExtension50PackageVersion>