[Bug][a11y]: Invalid tags require more than just color to identify as invalid

### Code of conduct

- [X] I agree to follow this project's code of conduct.

### Impacted component(s)

sp-tag

### Expected behavior

Invalid tags at least in the design, have an icon to indentify itself as invalid along with a different border color. https://spectrum.adobe.com/page/tag/#Error

### Actual behavior

The implementation https://opensource.adobe.com/spectrum-web-components/components/tags/ relies solely on color, which would fail the [Use of color criteria](https://accessibility.corp.adobe.com/testing/web/manual_checklist/#p_useofcolor)

### Screenshots

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### What browsers are you seeing the problem in?

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### How can we reproduce this issue?

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### Sample code that illustrates the problem

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### Logs taken while reproducing problem

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Start with the sp-tag component implementation linked in the issue and compare its invalid state with the Spectrum Tag error guidance. Verify how invalid tags are rendered and identify the change needed to provide a non-color indicator, then check the component's existing validation or accessibility coverage before confirming the behavior is complete.

Written by the indexing model from the issue text.