cvpcb: icon "select previous symbol" not working correctly

Description

The footprint-assignment tool (cvpcb) owns two icons to select the next / previous symbol without currently assigned footprint.

The "select previous symbol"-arrow gets stuck at already assigned symbols and doesn't jumps to the empty symbols at the top of the list.

affects v6.0.4 and v6.99. Low priority because direct symbol-selection (clicking with mouse into desired symbol-row) works correctly (and faster).

Steps to reproduce

1. open attached project, open schematic, open footprint assignment tool (cvpcb)
2. observe second column: only two symbols (J101/J102) are already associated with footprints
3. click 8x times on icon (arrow) "Select next symbol without footprint assignment" (see picture 1)
4. works, the blue selection-row goes down to last line (see picture 2)
5. now try the opposite: click 8x times on icon (arrow) "Select previous symbol without footprint assignment" (see picture 3)
6. observe: blue selection-row is stuck at row nr.7, it can't jump over J101/J102 (see picture 4)

cvpcb_previous_next_not_working.zip

KiCad Version

Application: KiCad Schematic Editor (64-bit)

Version: (6.99.0-1762-g453015586a), 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