Bump MudBlazor from 7.15.0 to 8.6.0

Bumps [MudBlazor](https://github.com/MudBlazor/MudBlazor) from 7.15.0 to 8.6.0.
- [Release notes](https://github.com/MudBlazor/MudBlazor/releases)
- [Changelog](https://github.com/MudBlazor/MudBlazor/blob/dev/CHANGELOG.md)
- [Commits](MudBlazor/MudBlazor@v7.15.0...v8.6.0)

---
updated-dependencies:
- dependency-name: MudBlazor
  dependency-version: 8.6.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Directory.Packages.props

@@ -17,7 +17,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageVersion>
     <PackageVersion Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.0" />
-    <PackageVersion Include="MudBlazor" Version="7.15.0" />
+    <PackageVersion Include="MudBlazor" Version="8.6.0" />
     <PackageVersion Include="Petabridge.Cmd.Cluster" Version="1.4.3" />
     <PackageVersion Include="Petabridge.Cmd.Cluster.Sharding" Version="1.4.3" />
   </ItemGroup>