🎨 Palette: Add missing tooltip text to discover account buttons

[dlukt]

Added the missing android:tooltipText attribute to the accept_btn and reject_btn ProgressBarButtons in item_discover_account.xml, which already had their corresponding contentDescription correctly set. This helps provide accessibility hover tips and long-press tooltips for sighted users navigating the discover accounts interface.

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PR created automatically by Jules for task 2830816257152494850 started by @dlukt

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