🎨 Palette: Add ARIA labels to message queue buttons

[thirdeyenation]

💡 What
Added aria-label attributes to the icon-only buttons in the Message Queue ("Send all", "Clear all", "Send now", "Remove"). Additionally, added aria-hidden="true" to the inner <span> elements containing the Material Symbols ligatures.

🎯 Why
Previously, these buttons relied solely on the title attribute for tooltip display, and screen readers might read the literal text of the ligature (e.g., "keyboard_double_arrow_right") instead of the action's intent. The added aria-labels provide clear descriptions for assistive technologies, and aria-hidden="true" prevents the screen reader from reading the icon text.

📸 Before/After
(No visual change - DOM attributes only)

♿ Accessibility

• Screen readers will now correctly announce the purpose of the message queue buttons.
• Prevented confusion from raw ligature strings being read aloud.

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PR created automatically by Jules for task 17820965554758756390 started by @thirdeyenation

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