Highlight net can activate while dragging

Description

Steps to reproduce

1. Open PIC Programmer demo project
2. Use g to grab/drag a component
3. While dragging, press ~ to highlight

In debug we get an assertion. In release, this crashes.

Peek_2022-02-15_10-41

KiCad Version

Application: KiCad Schematic Editor

Version: (6.99.0-948-g45a1a9a715), debug build

Libraries:
	wxWidgets 3.0.5
	FreeType 2.10.4

Platform: Linux 5.8.0-3-amd64 x86_64, 64 bit, Little endian, wxGTK, xfce, x11

	wxWidgets: 3.0.5 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.24
	Boost: 1.74.0
	OCC: 7.5.1
	Curl: 7.74.0
	ngspice: 34
	Compiler: GCC 10.2.1 with C++ ABI 1014

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON
	KICAD_STDLIB_DEBUG=OFF
	KICAD_STDLIB_LIGHT_DEBUG=ON
	KICAD_SANITIZE_ADDRESS=OFF
	KICAD_SANITIZE_THREADS=OFF