Bump Nullable.Extended.Analyzer from 1.14.6129 to 1.15.6169 (#967)

Bumps [Nullable.Extended.Analyzer](https://github.com/tom-englert/Nullable.Extended.Analyzer) from 1.14.6129 to 1.15.6169.
- [Release notes](https://github.com/tom-englert/Nullable.Extended.Analyzer/releases)
- [Commits](https://github.com/tom-englert/Nullable.Extended.Analyzer/commits)

---
updated-dependencies:
- dependency-name: Nullable.Extended.Analyzer
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Directory.Build.props

@@ -81,7 +81,7 @@
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
-        <PackageReference Include="Nullable.Extended.Analyzer" Version="1.14.6129">
+        <PackageReference Include="Nullable.Extended.Analyzer" Version="1.15.6169">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
         </PackageReference>