Remove implicit fallback to reflection-based serialization

[eiriktsarpalis]

Makes the following changes:

• Remove implicit fallback to reflection-based serialization. FixRemove implicit fallback to reflection-based serialization in System.Text.Json sourcegen #71714
• Include JsonSerializerContext in JsonSerializerOptions copy constructor. FixJsonSerializerOptions copy constructor should include the metadata resolver #71716. FixJsonSerializerOptions constructor is not copying the context  aspnetcore#38720.
• Move reflection-based converter resolution out of JsonSerializerOptions. FixSystem.Text.Json GetConverterFromAttribute need to be annotated for native aot #68878

[ghost]

Note regarding the new-api-needs-documentation label:

This serves as a reminder for when your PR is modifying a ref *.cs file and adding/modifying public APIs, to please make sure the API implementation in the src *.cs file is documented with triple slash comments, so the PR reviewers can sign off that change.

[ghost]

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Issue Details

---

Makes the following changes:

• Remove implicit fallback to reflection-based serialization. Fix Remove implicit fallback to reflection-based serialization in System.Text.Json sourcegen #71714
• Include JsonSerializerContext in JsonSerializerOptions copy constructor. Fix JsonSerializerOptions copy constructor should include the metadata resolver #71716. Fix JsonSerializerOptions constructor is not copying the context  aspnetcore#38720.
• Move reflection-based converter resolution out of JsonSerializerOptions. Fix System.Text.Json GetConverterFromAttribute need to be annotated for native aot #68878

Author:	eiriktsarpalis
Assignees:	-
Labels:	area-System.Text.Json, new-api-needs-documentation
Milestone:	-