context menu pad in FP-Editor: entry "unroute selected" useless

Description

The entry for command "unroute selected" is not used in the pad-context-menu in the FP-editor.

Removal of this command would clean-up the context-menu, which is currently already quite full and needs scrolling (depending at screen-size, resolution and windows-scaling).

Steps to reproduce

1. open FP-editor, open any FP, select any pad
2. RMB-click for context-menu
3. use the command "unroute selected" - nothing happens (command is only usefull for board-editor)

KiCad Version

Application: KiCad PCB Editor (64-bit)

Version: (6.99.0-4976-g75a4de4744), release build

Libraries:
	wxWidgets 3.2.1
	FreeType 2.12.1
	HarfBuzz 5.0.1
	FontConfig 2.14.1

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

	wxWidgets: 3.2.1 (wchar_t,wx containers)
	Boost: 1.80.0
	OCC: 7.6.2
	Curl: 7.86.0-DEV
	ngspice: 38
	Compiler: Visual C++ 1929 without C++ ABI

Build settings:
	KICAD_SPICE=ON