Padding handle for flowed texts doesn't work (for some users, but it just never works)

Summary:

The newly added padding functionality for text-in-a-shape also creates a handle for normal flowed texts. The handle, however, in the top right corner of a flowed text, cannot be dragged, so it's rather confusing.

Steps to reproduce:

• open Inkscape
• click and drag with the text tool to create a flowed text
• type some text
• drag on the square shaped handle in the top right corner

What happened?

Nothing.

What should have happened?

Option a): the handle should not exist if it does nothing

Option b): the handle should perform text padding

I'm for option b, @adam.belis said in the chat that he'd agree with that.

This bug should be fixed before the release of 1.2 as it looks rather strange.

Version info

Inkscape 1.2-dev (1e4f7a3e85, 2022-01-31)

    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:    1.16.0
    Pango version:    1.44.7
    HarfBuzz version: 2.6.4

    OS version:       Linux Mint 20.3