Description
Calling Log.CloseAndFlushAsync() when using ReloadableLogger as a static logger silently fails and does nothing.

Reproduction

1. Set the static logger to a ReloadableLogger.
2. Call Log.CloseAndFlushAsync().

Expected behavior
The ReloadableLogger should either:

• Support DisposeAsync() and properly flush the sinks
• Fall back to Dispose() if DisposeAsync() is not available,
• Throw an exception indicating the failure to close and flush.

Relevant package, tooling and runtime versions
Serilog 4.0.1