IcCheckbox automated accessibility failure

### Summary of the bug
A user has reported that the IcCheckbox has caused an automated accessibility failure with Accessibility Insights.

The tool identified the following error with the checkmark svg:

> Image function: every image must be coded as either meaningful or decorative
>
> Path: ic-checkbox,.checkmark
> Snippet: ``
> Coded as: decorative
> ARIA role: no value
> Accessible name: checkmark icon

This could be a false positive as the image has an accessible name so I'm not sure why the tool thinks it is decorative.

Start with the IcCheckbox checkmark SVG identified by Accessibility Insights, including its , class="checkmark", and ARIA output. Reproduce the report with Accessibility Insights and determine whether the image should be meaningful or decorative; done when the component no longer reports the failure and its intended accessible semantics are verified.

Written by the indexing model from the issue text.