Revert NuGet 7.6 release notes change

[Copilot]

The previously added "Summary: What's New in 7.6" section in the NuGet 7.6 release notes (documenting CRL/OCSP URL output in dotnet nuget verify) was placed in the wrong repo. The correct location is docs/core/tools/dotnet-nuget-verify.md in dotnet/docs.

Changes

• docs/release-notes/NuGet-7.6.md — Reverted the added section; file is net-unchanged from before.

The actual documentation update for NuGet.Client #7181 needs to be made in dotnet/docs at docs/core/tools/dotnet-nuget-verify.md.

[learn-build-service-prod]

Learn Build status updates of commit e402888:

⚠️ Validation status: warnings

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