update schematic from pcb: double update-message for some items

Description

The "Update schematic from pcb" allows to send footprint-info from pcb back to the board. A summary of all changes which are made in the schematic is displayed in the "Changes to be applied"-text-window.

Sometimes the change of a footprint/symbol is displayed twice.

Steps to reproduce

1. open attached project, open schematic, open board (both need to be open simultaneously)
2. inspect J103/J104 in the schematic: currently no footprint assigned
3. switch to board-editor, run "Tools-->Update Schematic from PCB"
4. set checkboxes (see picture):

• Relink footprints by reference designator
• assign values
• assign footprints

5. look at the message-window: J104 is displayed twice

update_schematic_from_pcb_01.zip

KiCad Version

Application: KiCad (64-bit)

Version: (6.99.0-1757-g37aa42d1e3), release build

Libraries:
	wxWidgets 3.1.5
	FreeType 2.11.1
	HarfBuzz 2.8.2
	FontConfig 2.13.1

Platform: Windows 10 (build 19044), 64-bit edition, 64 bit, Little endian, wxMSW

	wxWidgets: 3.1.5 (wchar_t,wx containers)
	Boost: 1.76.0
	OCC: 7.6.0
	Curl: 7.78.0-DEV
	ngspice: 36
	Compiler: Visual C++ 1929 without C++ ABI

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON