Bump Microsoft.AspNetCore.OpenApi from 8.0.15 to 8.0.19

---
updated-dependencies:
- dependency-name: Microsoft.AspNetCore.OpenApi
  dependency-version: 8.0.19
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

src/GraphEventGrid.csproj

@@ -15,7 +15,7 @@
 
   <ItemGroup>
     <PackageReference Include="Azure.Identity" Version="1.15.0" />
-    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="8.0.15" />
+    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="8.0.19" />
     <PackageReference Include="Microsoft.Graph" Version="5.91.0" />
     <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.556">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>