Bump MediatR from 12.2.0 to 12.4.0

Bumps [MediatR](https://github.com/jbogard/MediatR) from 12.2.0 to 12.4.0.
- [Release notes](https://github.com/jbogard/MediatR/releases)
- [Commits](jbogard/MediatR@v12.2.0...v12.4.0)

---
updated-dependencies:
- dependency-name: MediatR
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Directory.Packages.props

@@ -21,7 +21,7 @@
  <PackageVersion Include="Blazored.LocalStorage" Version="4.5.0" />
  <PackageVersion Include="BuildBundlerMinifier" Version="3.2.449" PrivateAssets="All" />
  <PackageVersion Include="FluentValidation" Version="11.9.1" />
- <PackageVersion Include="MediatR" Version="12.2.0" />
+ <PackageVersion Include="MediatR" Version="12.4.0" />
  <PackageVersion Include="Microsoft.AspNetCore.Components.Authorization" Version="8.0.8" />
  <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly" Version="8.0.4" />
  <PackageVersion Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="8.0.4" PrivateAssets="all" />