Remove long-obsolete MVC APIs targeted for removal

[Copilot]

Remove long-obsolete MVC APIs targeted for removal

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• You've included unit or integration tests for your change, where applicable.
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Remove obsolete MVC APIs and track removals in unshipped baselines

Description

This removes APIs that have been obsolete for multiple releases and were intended to be deleted.
The change trims the MVC surface area by removing dead compatibility APIs and obsolete overloads/members.

• MVC TagHelpers API cleanup

  • Removed obsolete ImageTagHelper constructor taking IWebHostEnvironment and TagHelperMemoryCacheProvider.
  • Removed obsolete ImageTagHelper.HostingEnvironment and ImageTagHelper.Cache members.

• MVC compatibility API removal

  • Removed CompatibilityVersion.
  • Removed obsolete SetCompatibilityVersion(...) extension methods from MVC builder/core builder extensions.
  • Removed tightly coupled obsolete compatibility infrastructure types:
    • MvcCompatibilityOptions
    • ConfigureCompatibilityOptions<TOptions>
  • Removed now-obsolete compatibility test coverage tied to those types.

• Model metadata API cleanup

  • Removed obsolete ModelMetadataIdentity.ForProperty(Type, string, Type) overload.
  • Updated tests to use the PropertyInfo-based overload.

• Public API baselines

  • Reverted all PublicAPI.Shipped.txt changes made by this PR.
  • Recorded corresponding removals in PublicAPI.Unshipped.txt with *REMOVED* entries for:
    • Mvc.TagHelpers
    • Mvc.Core
    • Mvc.Abstractions

// before
ModelMetadataIdentity.ForProperty(typeof(int), "Property1", typeof(string));

// after
ModelMetadataIdentity.ForProperty(
    typeof(MyContainer).GetProperty(nameof(MyContainer.Property1))!,
    typeof(int),
    typeof(MyContainer));

[Youssef1313]

@copilot Revert all changes to PublicAPI.Shipped.txt, and move the corresponding entries to PublicAPI.Unshipped.txt with *REMOVED* prefix.

[Copilot]

@copilot Revert all changes to PublicAPI.Shipped.txt, and move the corresponding entries to PublicAPI.Unshipped.txt with *REMOVED* prefix.

Done in 9a32e8d.

[dotnet-policy-service]

Thanks for identifying a breaking change.

@Youssef1313, @copilot, after you commit this PR please take the following actions, as part of the breaking changes announcement process:

• Create an announcement issue by using the ASP.NET Core breaking change issue template.
• Link the breaking change announcement issue from this PR.
• Remove the needs-breaking-change-announcement label.

[Youssef1313]

Announcements created: aspnet/Announcements#532 aspnet/Announcements#533 aspnet/Announcements#534

Docs dotnet/AspNetCore.Docs#37425 dotnet/AspNetCore.Docs#37426 dotnet/AspNetCore.Docs#37427