Plotting schematics other than pdf ignores more than one top level sheets

Description

More than one top level sheets are ignored when Plot function is used for other than PDF export. This happens with Postscript, SVG and DXF targets where "Plot all pages" plots each page separately. (PDF plots to one file which includes more than one top level sheet.)

Steps to reproduce

1. Project with more than two top level sheets.
2. File -> Plot... -> SVG, DXF or Postscript.
3. Plot All Pages.
4. Observe the files names in the Output Messages view and in the file system.

KiCad Version

Application: KiCad Schematic Editor x64 on x64

Version: 10.0.5-109-gb82a3242b0, release build

Libraries:
	wxWidgets 3.3.2 
	FreeType 2.13.3
	HarfBuzz 12.3.0
	FontConfig 2.17.1
	libcurl/8.18.0 Schannel zlib/1.3.1

Platform: Windows 11 (build 26100), 64-bit edition, 64 bit, Little endian, wxMSW
OpenGL: NVIDIA Corporation, NVIDIA GeForce GTX 1650/PCIe/SSE2, 4.6.0 NVIDIA 576.80

Build Info:
	Date: Aug 10 2026 05:15:32
	wxWidgets: 3.3.2 (wchar_t,STL containers)
	Boost: 1.90.0
	OCC: 7.9.2
	Curl: 8.18.0
	ngspice: 46
	Compiler: Visual C++ 1944 without C++ ABI
	KICAD_IPC_API=ON
	KICAD_USE_PCH=OFF

Locale: 
	Lang: fi_FI
	Enc: UTF-8
	Num: 1 234,5
	Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)