[net9.0] [msbuild] Improve the error message when the SupportedOSPlatformVersion is lower than the minimum. Fixes #21368. (#21369)

[rolfbjarne]

This isn't very user friendly:

ILLink : unknown error IL7000: An error occurred while executing the custom linker steps. Please review the build log for more information.
ILLINK : error MT0073: Microsoft.iOS 18.0.8337 does not support a deployment target of 10.0 for iOS (the minimum is 11.0). Please select a newer deployment target in your project's Info.plist or change the SupportedOSPlatformVersion property in your project file.
ILLINK : error MT2301: The linker step 'Setup' failed during processing: Microsoft.iOS 18.0.8337 does not support a deployment target of 10.0 for iOS (the minimum is 11.0). Please select a newer deployment target in your project's Info.plist or change the SupportedOSPlatformVersion property in your project file.
[...]/packages/microsoft.net.illink.tasks/8.0.8/build/Microsoft.NET.ILLink.targets(87,5): error NETSDK1144: Optimizing assemblies for size failed. Optimization can be disabled by setting the PublishTrimmed property to false.

So improve this to only show a single error message:

The SupportedOSPlatformVersion value '10.0' in the project file is lower than the minimum value '11.0'.

Fixes #21368.

This is a backport of #21369 (and a backport of #21344 was also required).

[vs-mobiletools-engineering-service2]

📚 [CI Build] Artifacts 📚

Artifacts were not provided.

Pipeline on Agent
Hash: [PR build]

[vs-mobiletools-engineering-service2]

💻 [CI Build] Tests on macOS X64 - Mac Sonoma (14) passed 💻

✅ All tests on macOS X64 - Mac Sonoma (14) passed.

Pipeline on Agent
Hash: b0d6ac47dcd2ff08b422d826aa40e7e986097dca [PR build]

[vs-mobiletools-engineering-service2]

💻 [CI Build] Windows Integration Tests passed 💻

✅ All Windows Integration Tests passed.

Pipeline on Agent
Hash: b0d6ac47dcd2ff08b422d826aa40e7e986097dca [PR build]

[vs-mobiletools-engineering-service2]

💻 [CI Build] Windows Integration Tests passed 💻

✅ All Windows Integration Tests passed.

Pipeline on Agent
Hash: b0d6ac47dcd2ff08b422d826aa40e7e986097dca [PR build]

[vs-mobiletools-engineering-service2]

💻 [CI Build] Tests on macOS M1 - Mac Monterey (12) passed 💻

✅ All tests on macOS M1 - Mac Monterey (12) passed.

Pipeline on Agent
Hash: b0d6ac47dcd2ff08b422d826aa40e7e986097dca [PR build]

[vs-mobiletools-engineering-service2]

💻 [CI Build] Tests on macOS M1 - Mac Ventura (13) passed 💻

✅ All tests on macOS M1 - Mac Ventura (13) passed.

Pipeline on Agent
Hash: b0d6ac47dcd2ff08b422d826aa40e7e986097dca [PR build]

[vs-mobiletools-engineering-service2]

✅ API diff for current PR / commit

NET (empty diffs)

• iOS: (empty diff detected)
• tvOS: (empty diff detected)
• MacCatalyst: (empty diff detected)
• macOS: (empty diff detected)

✅ API diff vs stable

.NET (No breaking changes)

• iOS: vsdrops gist (No breaking changes)
• tvOS: vsdrops gist (No breaking changes)
• MacCatalyst: vsdrops gist (No breaking changes)
• macOS: vsdrops gist (No breaking changes)

ℹ️ Generator diff

Generator Diff: vsdrops (html) vsdrops (raw diff) gist (raw diff) - Please review changes)

Pipeline on Agent
Hash: b0d6ac47dcd2ff08b422d826aa40e7e986097dca [PR build]

[vs-mobiletools-engineering-service2]

🚀 [CI Build] Test results 🚀

Test results

✅ All tests passed on VSTS: test results.

🎉 All 99 tests passed 🎉

Tests counts

✅ cecil: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (iOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (MacCatalyst): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (macOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (Multiple platforms): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (tvOS): All 1 tests passed. Html Report (VSDrops) Download
✅ framework: All 2 tests passed. Html Report (VSDrops) Download
✅ fsharp: All 4 tests passed. Html Report (VSDrops) Download
✅ generator: All 1 tests passed. Html Report (VSDrops) Download
✅ interdependent-binding-projects: All 4 tests passed. Html Report (VSDrops) Download
✅ introspection: All 4 tests passed. Html Report (VSDrops) Download
✅ linker: All 40 tests passed. Html Report (VSDrops) Download
✅ monotouch (iOS): All 7 tests passed. Html Report (VSDrops) Download
✅ monotouch (MacCatalyst): All 8 tests passed. Html Report (VSDrops) Download
✅ monotouch (macOS): All 9 tests passed. Html Report (VSDrops) Download
✅ monotouch (tvOS): All 7 tests passed. Html Report (VSDrops) Download
✅ msbuild: All 2 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 4 tests passed. Html Report (VSDrops) Download
✅ xtro: All 1 tests passed. Html Report (VSDrops) Download

Pipeline on Agent
Hash: b0d6ac47dcd2ff08b422d826aa40e7e986097dca [PR build]