For Tray search should search across all tabs, not just the active one

## Current behavior
When using the search function in CopyQ's tray, it only searches within the single tab that was last active, ignoring content in all other tabs.

## Expected behavior
The search function should search through all tabs in the tray, not just the active/current one, allowing users to find content regardless of which tab contains it.

## Additional context
This limitation makes it difficult to find content when users have multiple tabs and can't remember which specific tab contains the item they're looking for.

## System Information
- CopyQ version: 10.0.0
- Operating System: Ubuntu 24.04.2