Consolidated CaptureEvent API methods

[jamescrosswell]

Resolves #2713

The code previously contained an internal interface containing a single method which was essentially an overload of various different CaptureEvent methods that we have in the IHub interface:

namespace Sentry.Internal;

internal interface IHubEx : IHub
{
    SentryId CaptureEventInternal(SentryEvent evt, Hint? hint, Scope? scope = null);
}

This PR both removes both the IHubEx interface and combines what was previously two separate CaptureEvent overloads into a single method signature where the Hint and Scope parameters are optional.

[bitsandfoxes]

IHubEx be gone! 🔥
I suspect the order scope, hint for the optional parameters is due to us expecting that scopes are much more likely to be used than hints?
I like that none of the samples had to be touched.