pcbnew: differential routing can't be started

Description

Can't start differential routing from a set of pads due to the new DP gap warning message check introduced in commit 1a39c8e8. Disabling that check in code solved the problem.

Steps to reproduce

Open the example project file

  1. Open the attached project

    issue_differential_mod.zip

    (I modified the example from issue 21077)

  2. Try to route a differential pair starting from pads of connector J1

KiCad Version 

Application: KiCad PCB Editor x86_64 on x86_64

Version: 9.99.0-5019-gefa73a79b1, release build

Libraries:
	wxWidgets 3.2.8
	FreeType 2.13.3
	HarfBuzz 10.2.0
	FontConfig 2.15.0
	libcurl/8.14.1 OpenSSL/3.5.4 zlib/1.3.1 brotli/1.1.0 zstd/1.5.7 libidn2/2.3.8 libpsl/0.21.2 libssh2/1.11.1 nghttp2/1.64.0 nghttp3/1.8.0 librtmp/2.3 OpenLDAP/2.6.10

Platform: Debian GNU/Linux 13 (trixie), 64 bit, Little endian, wxGTK, X11, , tty
OpenGL: NVIDIA Corporation, NVIDIA GeForce RTX 4070/PCIe/SSE2, 4.6.0 NVIDIA 580.105.08

Build Info:
	Date: Jan 19 2026 01:32:59
	wxWidgets: 3.2.8 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.83.0
	OCC: 7.8.1
	Curl: 8.14.1
	ngspice: 44.2
	Compiler: GCC 14.2.0 with C++ ABI 1019
	KICAD_IPC_API=ON
	KICAD_USE_PCH=OFF

Locale: 
	Lang: en_US
	Enc: UTF-8
	Num: 1,234.5
	Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)