feat(serilog): support restrictedToMinimumLevel when configuring Serilog in code

[jamescrosswell]

Summary

Fixes #4957

• Added restrictedToMinimumLevel and levelSwitch parameters to all three Sentry() extension method overloads on LoggerSinkConfiguration
• These parameters are passed through to Serilog's underlying Sink() call, enabling per-sink minimum level filtering to be set in code
• Previously, per-sink minimum levels could only be configured via appsettings.json; this change unblocks MAUI users who configure Serilog in code

Usage

.WriteTo.Sentry(o =>
{
    o.MinimumBreadcrumbLevel = LogEventLevel.Debug;
    o.MinimumEventLevel = LogEventLevel.Error;
}, restrictedToMinimumLevel: LogEventLevel.Warning)

Test plan

• All existing Sentry.Serilog.Tests pass
• New tests added: Sentry_WithRestrictedToMinimumLevel_FiltersLogsBelow and Sentry_WithRestrictedToMinimumLevel_NoDsn_ParameterIsAccepted
• API approval snapshot files updated

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.57%. Comparing base (32a55e3) to head (2f79b30).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5181      +/-   ##
==========================================
- Coverage   74.06%   73.57%   -0.50%     
==========================================
  Files         501      487      -14     
  Lines       18113    17720     -393     
  Branches     3521     3433      -88     
==========================================
- Hits        13415    13037     -378     
+ Misses       3838     3830       -8     
+ Partials      860      853       -7     

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