properties panel: extra unwanted minus-sign added
# Description
Under some circumstances the properties panel adds a additional untyped minus-character. (most probably from an earlier typed negative value).
This happens reproducible with the steps below.
affects also v799.
# Steps to reproduce
1. open any board (or the attached project: [propertiespanel_textitem.zip](/uploads/c9c07d5e07ef98416487508e7f261998/propertiespanel_textitem.zip)
2. add a simple textitem near the 0,0 coordinate
3. use the properties panel for the next steps
4. set "Position y" to -10, ENTER (text should move some mm down)
5. click into Orientation field, type "20", ENTER
6. notice: the orientation accepts the value "-20", thus adding autonomous a negative sign.
7. Is this the first operation of a newly added AI?
# KiCad Version
```
Application: KiCad PCB Editor x64 on x64
Version: (7.0.0-160-g9b61b350fe), release build
Libraries:
wxWidgets 3.2.2
FreeType 2.12.1
HarfBuzz 5.0.1
FontConfig 2.14.1
Platform: Windows 10 (build 19044), 64-bit edition, 64 bit, Little endian, wxMSW
wxWidgets: 3.2.2 (wchar_t,wx containers)
Boost: 1.80.0
OCC: 7.6.2
Curl: 7.83.1-DEV
ngspice: 39
Compiler: Visual C++ 1934 without C++ ABI
Build settings:
KICAD_SPICE=ON
```
issue