Some old MSTest.pfx references were lingering (and now breaking things) (#2638)

Author: DrusTheAxe

test/TestApps/AccessControlTestAppPackage/AccessControlTestAppPackage.wapproj

@@ -64,10 +64,9 @@
     <Content Include="Images\Square44x44Logo.targetsize-24_altform-unplated.png" />
     <Content Include="Images\StoreLogo.png" />
     <Content Include="Images\Wide310x150Logo.scale-200.png" />
-    <None Include="MSTest.pfx" />
   </ItemGroup>
   <Import Project="$(WapProjPath)\Microsoft.DesktopBridge.targets" />
   <ItemGroup>
     <ProjectReference Include="..\AccessControlTestApp\AccessControlTestApp.vcxproj" />
   </ItemGroup>
-</Project>
+</Project>

test/TestApps/ToastNotificationsDemoPackage/ToastNotificationsDemoPackage.wapproj

@@ -42,7 +42,8 @@
     <EntryPointProjectUniqueName>..\ToastNotificationsDemoApp\ToastNotificationsDemoApp.vcxproj</EntryPointProjectUniqueName>
     <GenerateAppxPackageOnBuild>true</GenerateAppxPackageOnBuild>
     <GenerateAppInstallerFile>False</GenerateAppInstallerFile>
-    <PackageCertificateKeyFile>$(SolutionDir)temp\MSTest.pfx</PackageCertificateKeyFile>
+    <PackageCertificateKeyFile>$(RepoTestCertificatePFX)</PackageCertificateKeyFile>
+    <PackageCertificatePassword>$(RepoTestCertificatePassword)</PackageCertificatePassword>
     <AppxPackageSigningTimestampDigestAlgorithm>SHA256</AppxPackageSigningTimestampDigestAlgorithm>
     <AppxAutoIncrementPackageRevision>True</AppxAutoIncrementPackageRevision>
     <GenerateTestArtifacts>True</GenerateTestArtifacts>
@@ -85,4 +86,4 @@
   <ItemGroup>
     <ProjectReference Include="..\ToastNotificationsDemoApp\ToastNotificationsDemoApp.vcxproj" />
   </ItemGroup>
-</Project>
+</Project>