Utility function/decorator to mark things as Sentry-patched

[szokeasaurusrex]

While reviewing #3358, I had the idea that we might want to make it easier to detect when the SDK has already patched something. This came up because with the @ensure_integration_enabled decorator, the function's __name__ (and similar attributes) are overwritten to make the function look like the original function, so we cannot use these attributes to detect that a function has been patched by Sentry. I originally thought adding this would be necessary for that PR to work, but turns out we don't need it, so I am documenting this idea here, instead.

We could add this to the @ensure_integration_enabled decorator and/or make a separate decorator. The decorator would set an attribute called something like _sentry_patched on the patched function/class/etc. We could set this attribute simply to True, or if we want to make it more informative, maybe we can include some information about what patched the function (maybe the integration class/identifier – we can think about what would be the most helpful).