Document ObjectDisposedException for CsvReader.GetRecords overloads

[fuguiKz]

Fixes #2338

• Adds ObjectDisposedException XML docs to CsvReader.GetRecords<T>(T anonymousTypeDefinition) and CsvReader.GetRecords(Type type).
• Adds a regression test for the anonymous type overload to ensure it throws on deferred enumeration after disposal.

Tests:

• dotnet test tests/CsvHelper.Tests/CsvHelper.Tests.csproj -c Release -f net9.0 --filter FullyQualifiedName~CsvHelper.Tests.Reading.YieldTests

[fuguiKz]

Quick ping (no rush): this is doc-only + a small regression test for the deferred-enumeration-after-disposal case (Fixes #2338). No behavior change intended — just documenting the existing ObjectDisposedException contract and locking it in with a test. Happy to tweak wording/placement if you prefer.