Raise group of exceptions if many signal handlers fail

### Code of Conduct

- [x] I agree to follow Django's Code of Conduct

### Feature Description

Introduced in 3.11, [ExceptionGroup](https://docs.python.org/3/library/exceptions.html#lib-exception-groups) can be used to capture multiple exceptions, rather than just the first.

There should be an API which groups exceptions together and raises them at once at the end.

### Problem

When a signal has multiple receivers, `.send` will skip running future handlers if one fails. This may be undesirable in some cases, especially for custom signals.

### Request or proposal

request

### Additional Details

This is different to `send_robust`, as `send_robust` quietly ignores errors, whereas this API would allow the sender to handle any errors if necessary (or continue the same behaviour whilst allowing all handlers to run but still report an error afterwards)

### Implementation Suggestions

An additional API on `Signal` to `send_and_group` (name TBC) which runs all registered receivers, collects any exceptions and re-raises an `ExceptionGroup` with them.

Because the `ExceptionGroup` is a different exception to the inner exception, this can't be handled with the existing `.send` (I think?).

If no exception handling is done, it may be safe to update some internal implementations from `.send` to this.