bug(MatFormField): getConnectedOverlayOrigin includes form field hint area

### Is this a regression?

- [X] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

v14 (works w/ Legacy)

### Description

When migrating to the MDC-based components, the `getConnectedOverlayOrigin()` method on `MatFormField` now seems to point to the bottom of entire form field div (i.e. including the hint area) rather than the bottom edge of the input box. This makes it difficult to attach overlays to the bottom of custom form fields in a clean non-hacky way.

Basic example that demonstrates the problem:

1. Create a basic component that implements `MatFormFieldControl` (just directly copying the example [from the guide here](https://material.angular.io/guide/creating-a-custom-form-field-control) works for this).
2. Add a simple `mat-autocomplete` and wire it up to the input on the component.
3. Add a `MatAutocompleteOrigin` field to the component which points to the `MatFormField`'s `getConnectedOverlayOrigin()` (also may need to update this on ngOnInit to be safe).
4. Set the `matAutocompleteConnectedTo` in the template to the `MatAutocompleteOrigin` field.

Previously this would make the autocomplete overlay open lined up below the bottom edge of the form field, now there is an unsightly gap.

### Reproduction

StackBlitz link: https://stackblitz.com/edit/6vnpqz

Steps to reproduce:
1. Click the form field

### Expected Behavior

Attached overlay should appear directly below the form field's underline

### Actual Behavior

Attached overlay appears below the form field's hint area

### Environment

- Angular: 16.1.1
- CDK/Material: 16.2.9
- Browser(s): Chrome, Firefox
- Operating System (e.g. Windows, macOS, Ubuntu): Windows, Ubuntu

Start with the StackBlitz reproduction and the MatFormField.getConnectedOverlayOrigin() entry point, using the custom MatFormFieldControl and mat-autocomplete setup described in the issue. Confirm that the connected overlay is positioned directly below the form field underline rather than below the hint area.

Written by the indexing model from the issue text.