chore: Metrics - Add support for AOT

[hjgraca]

Please provide the issue number

Issue number: #212

Summary

Metrics support for AOT

Changes

Add new MetricsSerializationContext.cs for AOT source generated serialization Remove dependency from UniversalWrapperAspect.cs and refactor Metric attribute/decorator .NET8 specific paths in code Refactor EMFValidationTests.cs no more mocks

User experience

Please share what the user experience looks like before and after this change

Checklist

Please leave checklist items unchecked if they do not apply to your change.

• [x] Meets tenets criteria
• [x] I have performed a self-review of this change
• [x] Changes have been tested
• [ ] Changes are documented
• [x] PR title follows conventional commit semantics

Is this a breaking change?

**RFC issue number**: Checklist: * [ ] Migration process documented * [ ] Implement warnings (if it can live side by side)

Acknowledgment

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 72.55%. Comparing base (cb11aff) to head (d666ab2).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #602 +/- ## =========================================== + Coverage 72.30% 72.55% +0.24% =========================================== Files 190 190 Lines 7905 7900 -5 Branches 851 850 -1 =========================================== + Hits 5716 5732 +16 + Misses 1893 1877 -16 + Partials 296 291 -5 ``` | [Flag](https://app.codecov.io/gh/aws-powertools/powertools-lambda-dotnet/pull/602/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aws-powertools) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/aws-powertools/powertools-lambda-dotnet/pull/602/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aws-powertools) | `72.55% <100.00%> (+0.24%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aws-powertools#carryforward-flags-in-the-pull-request-comment) to find out more.

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