PDF Import: UX of selecting the page for Cairo/Poppler import

Summary:

It's not clear how to select a page for the Cairo/Poppler import.

Steps to reproduce:

• open Inkscape
• try to import a specific page from a PDF using Cairo/Poppler.

What happened?

• There is no page selector on the Cairo page.
• Changing the previewed page using the forward/back buttons while on the Cairo page has no effect on the page to be imported.
• If a single page is entered into the field on the "Internal import" page, the setting applies to the Cairo import as well.

What should have happened?

Just a page selector on the Cairo page.

Sample attachments:

Version info

Inkscape 1.3-dev (7e1a6f8, 2023-02-24)

    GLib version:     2.64.6
    GTK version:      3.24.20
    glibmm version:   2.64.2
    gtkmm version:    3.24.2
    libxml2 version:  2.9.10
    libxslt version:  1.1.34
    Cairo version:    1.17.7
    Pango version:    1.44.7
    HarfBuzz version: 2.6.4

    OS version:       Ubuntu 22.04.2 LTS