More trimming fixes, enable analyzers unconditionally

[maxkatz6]

What does the pull request do?

After that PR simple Avalonia Hello World produces 0 trimming related warnings/errors in AOT mode.
Note, even before this PR all of these warnings were false positives, without actual runtime errors. But it's always nicer to avoid warnings.

What was changed in this PR:

1. Avoid #pragma warning disable , when UnconditionalSuppressMessage should be used. Otherwise suppressions won't be respected in NAOT compilation.
2. Don't instantiate ReflectionMethodAccessorPlugin at all, when dynamic code isn't enabled.
3. Suppress Expression.OperatorName warnings, as this method is only used in design time.
4. Fix missing attribute on WinRTInspectable.

TODO:
Not related to warnings, but we can improve output binary size by respecting IsDynamicCodeSupported property in more places. But even better to wait until feature switches in .NET 9, so whole reflection bindings related codebase can be disabled and trimmed out.

We also should start running some tests with AOT enabled. MSTest might be required to do so, since xUnit doesn't support AOT yet.

Fixed issues

Fixes #13897
Fixes #11727

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0048618-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]