🎨 Palette: Add tooltip text to poll option buttons

[dlukt]

💡 What: Added android:tooltipText to the "Add poll option" and "Delete poll option" buttons in the compose view.
🎯 Why: To improve accessibility. These buttons already had contentDescription for screen readers, but missing tooltipText meant that users interacting with a mouse or stylus, or users who long-press for hints, would not see a textual description on API 26+ devices.
♿ Accessibility: Aligns the visual tooltip experience with the existing screen reader experience.

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PR created automatically by Jules for task 3241435001704794704 started by @dlukt

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