Make new extension actions only available to extensions, not to general UI

Summary:

With the new action

• 'Add bounding box information to all shapes': adds inkscape:visualbox and inkscape:geometricbox attributes

all objects in the drawing (including groups, ...) get those parameters.

• 'Add shape path information to all shapes': adds inkscape:d attribute

all 'terminal' objects (shapes as per definition in Inkscape terminology (circle, star, rectangle, spiral) + paths) get that information.

1. The descriptions do not match Inkscape's terminology
2. When moving any of those objects with those attributes around, or editing them, the attributes do not update.

Steps to reproduce:

• open Inkscape
• draw a couple paths and rectangles, group some of them
• in the commands palette, use both commands.
• move objects around

What happened?

1. the descriptions are misleading, the commands do not do what you'd expect
2. the new attributes never update (title changed from 'inkscape:d, inkscape:visualbox and inkscape:geometricbox attributes are not updated')

What should have happened?

No idea. I don't know what their purpose is. It seems to me they should be updating. Descriptions should at least be accurate.

Version info

Inkscape 1.4-dev (b151c3d5be, 2024-01-29)

                      Compile  (Run)
    GLib version:     2.72.4
    GTK version:      3.24.33 (3.24.33)
    glibmm version:   2.66.2
    gtkmm version:    3.24.5
    libxml2 version:  2.9.13
    libxslt version:  1.1.34
    Cairo version:    1.16.0 (1.16.0)
    Pango version:    1.50.6 (1.50.6)
    HarfBuzz version: 2.7.4 (2.7.4)

    OS version:       Linux Mint 21.3