Acceptance Criteria

- [x] Update Use in Playground to be a filled button and labelled
“Search in Playground” (not empty button)
- [x] Include View in Discover as a default button in page header
- [x] Hide 'Add reference' in context menu when documents not presented
in index to avoid duplication of this button
- [x] Add Spacer in settings

<img width="1212" alt="image"
src="https://github.com/user-attachments/assets/bcdfca68-b30f-4597-9e80-b0f27fcf6c9b">
<img width="1212" alt="image"
src="https://github.com/user-attachments/assets/48d78874-806f-4ba1-bca6-ba5516e4fcfa">

(cherry picked from commit 01d32b0)

# Backport

This will backport the following commits from `main` to `8.x`:
- [[Search] Onboarding ux improvements
(#196726)](#196726)

<!--- Backport version: 9.4.3 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

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Onboarding ux improvements (#196726)\n\nAcceptance Criteria\r\n\r\n- [x]
Update Use in Playground to be a filled button and labelled\r\n“Search
in Playground” (not empty button)\r\n- [x] Include View in Discover as a
default button in page header\r\n- [x] Hide 'Add reference' in context
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Onboarding ux improvements (#196726)\n\nAcceptance Criteria\r\n\r\n- [x]
Update Use in Playground to be a filled button and labelled\r\n“Search
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default button in page header\r\n- [x] Hide 'Add reference' in context
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Onboarding ux improvements (#196726)\n\nAcceptance Criteria\r\n\r\n- [x]
Update Use in Playground to be a filled button and labelled\r\n“Search
in Playground” (not empty button)\r\n- [x] Include View in Discover as a
default button in page header\r\n- [x] Hide 'Add reference' in context
menu when documents not presented\r\nin index to avoid duplication of
this button\r\n- [x] Add Spacer in settings\r\n\r\n<img width=\"1212\"
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BACKPORT-->

Co-authored-by: Yan Savitski <[email protected]>