feat: remove welcome canvas #22

Job	Run time
Build Debug / flatpak	7m 56s
Build Debug / build (ubuntu-20.04, 5, linux, 5.12.8, qtnetworkauth)	2m 26s
Build Debug / build (ubuntu-20.04, 6, linux, 6.2.4, qt5compat qtimageformats qtnetworkauth)	3m 40s
Build Debug / build (windows-2022, Windows-MinGW-w64, clang64, amd64_x86)	11m 38s
Build Debug / build (windows-2022, Windows-MSVC, x64, amd64, 6, windows, 6.7.1, qt5compat qtimageformats qtnetw...	6m 59s
Build Debug / build (windows-2022, Windows-MSVC-arm64, arm64, amd64_arm64, 6, windows, win64_msvc2019_arm64, 6....	5m 17s
Build Debug / build (macos-12, macOS, 11, 6, mac, 6.7.1, qt5compat qtimageformats qtnetworkauth)	8m 47s
Build Debug / build (macos-12, macOS-Legacy, 10.13, 5, mac, 5.15.2, qtnetworkauth)	3m 51s
	50m 34s

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