build(deps): bump Microsoft.Xaml.Behaviors.Wpf in /src

Bumps [Microsoft.Xaml.Behaviors.Wpf](https://github.com/microsoft/XamlBehaviorsWpf) from 1.1.39 to 1.1.77.
- [Release notes](https://github.com/microsoft/XamlBehaviorsWpf/releases)
- [Commits](microsoft/XamlBehaviorsWpf@v1.1.39...v1.1.77)

---
updated-dependencies:
- dependency-name: Microsoft.Xaml.Behaviors.Wpf
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

src/ReactiveUI.Blend/ReactiveUI.Blend.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="MSBuild.Sdk.Extras">
+<Project Sdk="MSBuild.Sdk.Extras">
 
   <PropertyGroup>
     <TargetFrameworks>net462;net472;net6.0-windows10.0.17763.0;net7.0-windows10.0.17763.0</TargetFrameworks>
@@ -21,7 +21,7 @@
 
   <ItemGroup>
     <Compile Include="Platforms\net4\**\*.cs" />
-    <PackageReference Include="Microsoft.Xaml.Behaviors.Wpf" Version="1.1.39" />
+    <PackageReference Include="Microsoft.Xaml.Behaviors.Wpf" Version="1.1.77" />
   </ItemGroup>
 
   <ItemGroup>