[7.99] Startup error hidden by splash image / Startup image shown in front of all other windows

Description

Testing for another bug I accidentally tried to right click open a pcbnew file with the context entry for 7.99 (right click -> open with -> Kicad 7.99). It therefore tried to open the pcbnew file as a project, which resulted in this error (probably to be expected, though I would suggest it could be detecting the file type and open it it pcbnew then):

But, the real issue here is: the error window is hidden from view by the startup splash, which actually is set in front of every application (and stays there indefinitely):

Since the error window can't be seen or closed directly, one needs to realize it's there, then close the window from the application bar.

The splash being set in front of all other applications might be considered not ideal, too, since it covers other programs, even if the application is just only running in the background:

Steps to reproduce

1. Try opening a pcbnew file via the context menu entry for 7.99
2. Find the error window hidden by the startup KiCAD image
3. Realize the startup splash stays in front of all open applications (and its own error windows) even if other applications should be in front.

KiCad Version

Application: KiCad x64 on x64

Version: 7.99.0-1755-gbb27f09108, release build

Libraries:
	wxWidgets 3.2.2
	FreeType 2.12.1
	HarfBuzz 6.0.0
	FontConfig 2.14.1
	libcurl/7.88.1-DEV Schannel zlib/1.2.13

Platform: Windows 11 (build 22621), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
	Date: Jul  6 2023 08:33:26
	wxWidgets: 3.2.2 (wchar_t,wx containers)
	Boost: 1.81.0
	OCC: 7.7.1
	Curl: 7.88.1-DEV
	ngspice: 40
	Compiler: Visual C++ 1936 without C++ ABI

Build settings: