MINOR: [C#] Bump Microsoft.NET.Test.Sdk from 15.8.0 to 17.7.0 in /csharp

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 15.8.0 to 17.7.0.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Changelog](https://github.com/microsoft/vstest/blob/main/docs/releases.md)
- [Commits](microsoft/vstest@v15.8.0...v17.7.0)

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

csharp/test/Apache.Arrow.Compression.Tests/Apache.Arrow.Compression.Tests.csproj

@@ -7,7 +7,7 @@
  </PropertyGroup>
 
  <ItemGroup>
- <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.5.0" />
+ <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.7.0" />
  <PackageReference Include="xunit" Version="2.4.0" />
  <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0" />
  </ItemGroup>

csharp/test/Apache.Arrow.Flight.Tests/Apache.Arrow.Flight.Tests.csproj

@@ -6,7 +6,7 @@
  </PropertyGroup>
 
  <ItemGroup>
- <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.5.0" />
+ <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.7.0" />
  <PackageReference Include="xunit" Version="2.4.0" />
  <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0" />
  <PackageReference Include="coverlet.collector" Version="6.0.0" />

csharp/test/Apache.Arrow.Tests/Apache.Arrow.Tests.csproj

@@ -10,7 +10,7 @@
  </PropertyGroup>
 
  <ItemGroup>
- <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.8.0" />
+ <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.7.0" />
  <PackageReference Include="xunit" Version="2.4.0" />
  <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0">
  <PrivateAssets>all</PrivateAssets>