SDKAnalysisLevel should call out the fact that it ages out

[nkolev92]

Describe the issue or suggestion

https://learn.microsoft.com/en-us/dotnet/core/project-sdk/msbuild-props#sdkanalysislevel.

During the design of the SDKAnalysisLevel feature we said it'll age out in 3 releases, namely 11.0.100 only has to respect up to 8.0.100 the most.
12.0.100, features that could be disabled by 8.0.100 will no longer be disabled.

cc @baronfel

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Document Details

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• ID: cb4428fc-215c-78e1-5ff0-fe73f7a08260
• Version Independent ID: 6741b1de-38a4-fbb1-d79d-acc47d549a2d
• Platform ID: eeaf76f8-da20-9011-c5e7-db6166523403
• Content: MSBuild properties for Microsoft.NET.Sdk - .NET
• Content Source: docs/core/project-sdk/msbuild-props.md
• Service: dotnet-fundamentals
• GitHub Login: @gewarren
• Microsoft Alias: gewarren