Interactive router differential doesn't take differential pair gap into account

Description

When routing with DP gap is used. However, when shoving or using any other interactive router option, only clearance is used.

Currently, to move the differential pair, I have to go to the board and change class clearance temporarily.

I understand that sometimes tracks need to get closer than the DP specifies, so maybe depending on whether one or two differential tracks are selected different gaps should be used.

Moving diff pairs.mp4

Steps to reproduce

1. Add differential pairs or use the example file differential_pairs_MidLayer4.kicad_pcb
2. Set Interactive router mode to Shove to experience the issue best
3. Ctrl+D to drag one of the differential pair

KiCad Version

Application: KiCad PCB Editor x64 on x64

Version: 7.99.0-3676-g2604854221, release build

Libraries:
	wxWidgets 3.2.4
	FreeType 2.12.1
	HarfBuzz 8.2.1
	FontConfig 2.14.2
	libcurl/8.4.0-DEV Schannel zlib/1.3

Platform: Windows 11 (build 22631), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
	Date: Nov 22 2023 06:18:17
	wxWidgets: 3.2.4 (wchar_t,wx containers)
	Boost: 1.83.0
	OCC: 7.7.1
	Curl: 8.4.0-DEV
	ngspice: 41
	Compiler: Visual C++ 1936 without C++ ABI

Build settings: