ci: Build the flutter test launcher too #1115

Job	Run time
build (ubuntu-latest, ci-dev-qt5, 5.15)	25m 43s
build (ubuntu-latest, ci-release-qt5, 5.15)	2m 41s
build (ubuntu-latest, ci-qtwidgets-qt5, 5.15)	2m 18s
build (ubuntu-latest, ci-qtquick-qt5, 5.15)	2m 23s
build (ubuntu-latest, ci-dev-qt6, 6.3.*)	22m 52s
build (ubuntu-latest, ci-release-qt6, 6.3.*)	3m 16s
build (ubuntu-latest, ci-qtwidgets-qt6, 6.3.*)	2m 26s
build (ubuntu-latest, ci-qtquick-qt6, 6.3.*)	2m 25s
build (windows-latest, ci-dev-qt5, 5.15)	26m 37s
build (windows-latest, ci-release-qt5, 5.15)	3m 2s
build (windows-latest, ci-qtwidgets-qt5, 5.15)	2m 45s
build (windows-latest, ci-qtquick-qt5, 5.15)	2m 53s
build (windows-latest, ci-dev-qt6, 6.3.*)	25m 18s
build (windows-latest, ci-release-qt6, 6.3.*)	3m 52s
build (windows-latest, ci-qtwidgets-qt6, 6.3.*)	3m 3s
build (windows-latest, ci-qtquick-qt6, 6.3.*)	3m 9s
build (macos-latest, ci-dev-qt5, 5.15)	28m 57s
build (macos-latest, ci-release-qt5, 5.15)	2m 59s
build (macos-latest, ci-qtwidgets-qt5, 5.15)	4m 41s
build (macos-latest, ci-qtquick-qt5, 5.15)	2m 24s
build (macos-latest, ci-dev-qt6, 6.3.*)	22m 52s
build (macos-latest, ci-release-qt6, 6.3.*)	6m 27s
build (macos-latest, ci-qtwidgets-qt6, 6.3.*)	2m 18s
build (macos-latest, ci-qtquick-qt6, 6.3.*)	2m 36s
build (ubuntu-latest, ci-python-qt6, 6.6.0, 0, llvm, shiboken6-generator==6.6.0 pyside6==6.6.0)	3m 42s
	3h 31m 39s

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