🎨 Palette: [Accessibility] Improve keyboard navigation and semantic HTML in Language Switcher & Gmaps Button

[Twinber]

💡 What: Upgraded LanguageSwitcher elements from <span> tags with onClick to accessible <button> components. Restructured GmapsButton to accurately merge button styling over a proper <a> link.
🎯 Why: Enhances overall keyboard navigation by rendering native focus outlines and removes invalid interactive HTML patterns (buttons inside links/links masquerading as buttons).
📸 Before/After: Visual outline for focused interactive elements ensures robust accessibility for power users and impaired individuals.
♿ Accessibility:

• Added aria-label to language options.
• Added aria-current to accurately reflect the active locale.
• Preserved anchor element semantics for screen readers instead of a <button> tag inside a link.

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PR created automatically by Jules for task 6310727798776677104 started by @Twinber

[google-labs-jules]

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