Undefined array key "id" in uswds_preprocess_form_element()

Problem/Motivation

uswds_preprocess_form_element() does not properly check for the existence of a form element's id key before trying to access it.

Steps to reproduce

1. Install the webform module
2. Create a webform
3. Add a text field with a maximum word length
4. Save and browse to the form
5. Attempt to submit the form with a value that exceeds the maximum word length

Expected: A validation message appears
Actual: A validation message appears, but also you get:

Warning: Undefined array key "id" in uswds_preprocess_form_element() (line 32 of themes/contrib/uswds/preprocess/element/form_element.preprocess.inc).

Proposed resolution

The line in question is:

$variables['error_id'] = $variables['element']['#attributes']['id']; But as far as I can tell the error_id value is never used. I believe the correct solution is to simply remove this line.

Remaining tasks

None

User interface changes

None

API changes

None

Data model changes

None