Update dotnet.aspnetcore to 8.0.21

[xdev-renovate]

This PR contains the following updates:

Package	Type	Update	Change
Microsoft.AspNetCore.Mvc.NewtonsoftJson (source)	nuget	patch	8.0.20 -> 8.0.21
Microsoft.Extensions.FileProviders.Embedded (source)	nuget	patch	8.0.20 -> 8.0.21

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Release Notes

dotnet/aspnetcore (Microsoft.AspNetCore.Mvc.NewtonsoftJson)

v8.0.21: .NET 8.0.21

Release

What's Changed

• Update branding to 8.0.21 by @​vseanreesermsft in #​63509
• [release/8.0] (deps): Bump src/submodules/googletest from 373af2e to eb2d85e by @​dependabot[bot] in #​63500
• [release/8.0] Make duplicate deb/rpm packages so we can sign them with the new PMC key by @​github-actions[bot] in #​63250
• [release/8.0] Extend Unofficial 1ES template in IdentityModel nightly tests job by @​github-actions[bot] in #​63466
• [release/8.0] Quarantine ResponseBody_WriteContentLength_PassedThrough by @​github-actions[bot] in #​63534
• [release/8.0] Update dependencies from dotnet/source-build-reference-packages by @​dotnet-maestro[bot] in #​63261
• [release/8.0] Use wait assert in flaky tests by @​ilonatommy in #​63565
• [release/8.0] Update Microsoft.Build versions by @​github-actions[bot] in #​62507
• Merging internal commits for release/8.0 by @​vseanreesermsft in #​63603
• backport(8.0): Fix runtime architecture detection logic in ANCM by @​DeagleGross in #​63706

Full Changelog: dotnet/aspnetcore@v8.0.20...v8.0.21

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