Length/skew tuning dialogs: values becomes negative

Description

When specifying a large "Target length" in "Single Track Length Tuning" dialog, after re-opening the dialog, the value becomes negative.

Also applies to "Differential Pair Length Tuning" and "Differential pair skew tuning".

Steps to reproduce

1. Add a track
2. Invoke "Tune length of single track" tool
3. Click on "Length Tuning Settings..." context menu item
4. Set "Target length" to 3000 mm (or any value >= 2147.483648)
5. Re-open the dialog
6. The value is set to -1294.967296 mm

Through the tool sees the proper value:

KiCad Version

Application: KiCad PCB Editor (64-bit)

Version: (6.0.2-36-g89384375d9-dirty), release build

Libraries:
	wxWidgets 3.1.5
	libcurl/7.78.0-DEV Schannel zlib/1.2.11

Platform: Windows 10 (build 18363), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
	Date: Feb 16 2022 12:11:34
	wxWidgets: 3.1.5 (wchar_t,wx containers)
	Boost: 1.76.0
	OCC: 7.5.0
	Curl: 7.78.0-DEV
	Compiler: Visual C++ 1930 without C++ ABI

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=OFF

(based on 71eefc83)