Crash when pasting onto an undone sheet

Steps to reproduce

1. Create a new sheet on a root sheet
2. Copy a symbol
3. Go into the sheet
4. Undo
5. Paste the symbol
6. Crash
7. After crash, this message is shown:

(KiCad is installed in S:\Program Files\KiCad\6.0 and a "sonde xilinx" demo project was open)

8. After clicking OK, last project before the crash opens.

(Separated from #10504 (closed))

KiCad Version

Application: KiCad (64-bit)

Version: (6.0.1), 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: Jan 15 2022 13:36:27
	wxWidgets: 3.1.5 (wchar_t,wx containers)
	Boost: 1.76.0
	OCC: 7.5.0
	Curl: 7.78.0-DEV
	ngspice: 35
	Compiler: Visual C++ 1929 without C++ ABI

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON