Suppress NuGet known package vulnerability alert (#23767)

Author: vidai-msft

src/Az.Shared.props

@@ -16,6 +16,8 @@
     <GenerateAssemblyTitleAttribute>false</GenerateAssemblyTitleAttribute>
     <GenerateAssemblyVersionAttribute>false</GenerateAssemblyVersionAttribute>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <!-- Suppress known NuGet package vulnerabilities to unblock build as we track this kind of security issues internally. -->
+    <WarningsNotAsErrors>NU1901;NU1902;NU1903;NU1904</WarningsNotAsErrors>
     <WarningsAsErrors />
   </PropertyGroup>