dialog: Fix save file chooser with xdg portal #7014

Job	Run time
Create test plan	8s
level1 / Haiku	1m 35s
level2 / Steam Linux Runtime 3.0 (arm64)	2m 10s
level2 / MacOS (Framework) (x64)	5m 26s
level2 / Windows (MSVC, ARM64)	3m 50s
level2 / iOS (CMake & xcode)	3m 26s
level2 / N-Gage	3m 47s
level2 / Ubuntu 24.04 (ARM64)	4m 37s
level2 / Windows (msys2, clang64)	4m 21s
level2 / LoongArch64	3m 0s
level2 / MacOS (Framework) (arm64)	4m 7s
level2 / Windows (MSVC, ARM)	3m 29s
level2 / Steam Linux Runtime 3.0 (x86_64)	2m 52s
level2 / Ubuntu 22.04 (Intel Compiler)	3m 49s
level2 / Windows (MSVC, x64)	5m 10s
level2 / Sony PlayStation Vita (GLES w/ PVR_PSP2)	2m 56s
level2 / Android (Gradle)	2m 36s
level2 / tvOS (CMake & xcode)	3m 23s
level2 / GDK (MSVC, x64)	1m 50s
level2 / Windows (MSVC, clang-cl x86)	4m 56s
level2 / RISC OS	1m 21s
level2 / Emscripten	9m 35s
level2 / Windows (msys2, mingw32)	4m 40s
level2 / Windows (msys2, mingw64)	4m 7s
level2 / Windows (msys2, ucrt64)	4m 17s
level2 / Sony PlayStation Portable	4m 35s
level2 / Windows (MSVC, x86)	5m 9s
level2 / MacOS (GNU prefix)	5m 50s
level2 / Android (CMake)	5m 20s
level2 / Sony PlayStation Vita (GLES w/ pib)	3m 1s
level2 / Ubuntu 22.04	2m 38s
level2 / Sony PlayStation 2	6m 6s
level2 / NetBSD	4m 33s
level2 / PowerPC	2m 36s
level2 / Windows (MSVC, clang-cl x64)	5m 1s
level2 / Nintendo 3DS	2m 25s
level2 / FreeBSD	2m 55s
level2 / Android (CMake, lean)	5m 58s
level2 / Android (Android.mk)	2m 11s
level2 / Ubuntu 22.04 (Intel oneAPI)	5m 3s
level2 / PowerPC64	2m 0s
	2h 36m 49s

Provide feedback