[Blazor] Fix scoped CSS hot reload (#42137)

Author: MackinnonBuck

src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.ScopedCss.targets

@@ -83,6 +83,15 @@ Integration with static web assets:
 
 </PropertyGroup>
 
+<PropertyGroup>
+
+  <GenerateComputedBuildStaticWebAssetsDependsOn Condition="'$(DisableScopedCssBundling)' != 'true'">
+    $(GenerateComputedBuildStaticWebAssetsDependsOn);
+    BundleScopedCssFiles;
+  </GenerateComputedBuildStaticWebAssetsDependsOn>
+
+</PropertyGroup>
+
 <Target Name="GenerateScopedCssFiles" DependsOnTargets="$(GenerateScopedCssFilesDependsOn)" />
 
 <Target Name="ResolveScopedCssAssets" DependsOnTargets="$(ResolveScopedCssAssetsDependsOn)">

src/StaticWebAssetsSdk/Tasks/Data/StaticWebAsset.cs

@@ -249,7 +249,7 @@ internal static (string fingerprint, string integrity) ComputeFingerprintAndInte
 
         internal static string ComputeIntegrity(string identity, string originalItemSpec)
         {
-            var file = File.Exists(identity) ?
+            using var file = File.Exists(identity) ?
     File.OpenRead(identity) :
     (File.Exists(originalItemSpec) ?
         File.OpenRead(originalItemSpec) :