Allow copy-paste of formatting inside a text object
#### Summary:
At present, Ctrl+Shift+V can be used to paste the formatting from one object to another. However, this does not work for spans of text inside a text object.
#### Steps to reproduce:
- Open Inkscape.
- Create a text object and write the words “Foo Bar Baz”.
- Select the word “Bar” and give it some deviant formatting, e.g. fill, stroke, italic, etc.
- Press Ctrl+C to copy the selected span containing the newly formatted word “Bar”.
- Create another text object and write the words “Snap Crackle Pop”.
- Select the word “Crackle”.
- Press Ctrl+Shift+V.
#### What happened?
It pastes the overall formatting of the original text object, not the specially-formatted “Bar” span.
#### What should have happened?
It should paste the formatting of the “Bar” span.
#### Version info
```
Inkscape 1.4.2 (f4327f4, 2025-05-13)
Compile (Run)
GLib version: 2.84.0
GTK version: 3.24.49 (3.24.49)
glibmm version: 2.66.7
gtkmm version: 3.24.9
libxml2 version: 2.12.10
libxslt version: 1.1.43
Cairo version: 1.18.4 (1.18.4)
Pango version: 1.56.3 (1.56.3)
HarfBuzz version: 10.4.0 (10.4.0)
OS version: Windows 10 22H2
```
issue