feat(FormField): Support error icons

### Feature Description

Material Design 3 guidelines [recommend showing an error icon when a text field is in an error state](https://m3.material.io/components/text-fields/guidelines#:~:text=It%E2%80%99s%20strongly%20recommended,additional%20sensory%20indicator.). However, there is no [such example in the Form Field documentation](https://material.angular.dev/components/form-field/examples) and no references to this in the overview section of the documentation.

If this is supported, it should be a added to the documentation. If not, support should be added.

### Use Case

_No response_

Start with the Form Field documentation examples and overview referenced in the issue, then inspect the existing error-state behavior to determine whether error icons are already supported. Done means documenting a working error-icon example and overview reference, or adding support before documenting it if the current component cannot provide one.

Written by the indexing model from the issue text.