Page buttons are displayed at the top of the form in editor mode

[CharlesGrimont]

Page buttons are displayed at the top of the form in editor mode, while they should appear at the bottom of the form.

Current behavior:

• In editor mode, page buttons are rendered at the top of the form.
• This differs from the expected form layout and can make the editor preview misleading.

Expected behavior:

• Page buttons should be displayed at the bottom of the form in editor mode.
• Their position should match the expected form structure and viewer behavior where applicable.

Acceptance criteria:

• Page buttons appear at the bottom of the form in editor mode.
• Button placement remains stable after editor refresh and page switch.
• No regression on viewer mode button placement.
• No regression on forms without page buttons.

[github-actions]

To be tested in 2.2.0-beta111

[gregory-vorbe]

OK in 2.2.0-beta112