Revert "Merge pull request matplotlib#30535 from LangQi99/fix/import"

Upstream has fixed PyGObject in 3.51.1.

This reverts commit 75e7802, reversing
changes made to 352b419.

Author: QuLogic

lib/matplotlib/backends/backend_gtk3.py

@@ -18,13 +18,6 @@
     # :raises ValueError: If module/version is already loaded, already
     # required, or unavailable.
     gi_require_version("Gtk", "3.0")
-    # Also require GioUnix to avoid PyGIWarning when Gio is imported
-    # GioUnix is platform-specific and may not be available on all systems
-    try:
-        gi_require_version("GioUnix", "2.0")
-    except ValueError:
-        # GioUnix is not available on this platform, which is fine
-        pass
 except ValueError as e:
     # in this case we want to re-raise as ImportError so the
     # auto-backend selection logic correctly skips.

lib/matplotlib/backends/backend_gtk4.py

@@ -17,13 +17,6 @@
     # :raises ValueError: If module/version is already loaded, already
     # required, or unavailable.
     gi_require_version("Gtk", "4.0")
-    # Also require GioUnix to avoid PyGIWarning when Gio is imported
-    # GioUnix is platform-specific and may not be available on all systems
-    try:
-        gi_require_version("GioUnix", "2.0")
-    except ValueError:
-        # GioUnix is not available on this platform, which is fine
-        pass
 except ValueError as e:
     # in this case we want to re-raise as ImportError so the
     # auto-backend selection logic correctly skips.