Update RPM build to Fedora 41 (#10021)

* Update RPM build to Fedora 41

Fedora 41 was released on 2024-10-29, cf. https://discussion.fedoraproject.org/t/fedora-linux-41-is-here/134766.

Current builds (tried `mozillavpn-2.25.0~build20241108-1.x86_64` downloaded from https://github.com/mozilla-mobile/mozilla-vpn-client/actions/runs/11733374458) depend upon `libQt6Core.so.6(Qt_6.7_PRIVATE_API)(64bit)` but since Fedora 41 is on Qt 6.8 no current package provides that symbol.

* Install GDB


Signed-off-by:  Basti

.github/workflows/linux.yaml

@@ -60,7 +60,7 @@ jobs:
       - name: Install Build Dependencies
         run: |
           dnf -y update
-          dnf -y install rpmdevtools 'dnf-command(builddep)'
+          dnf -y install gdb rpmdevtools 'dnf-command(builddep)'
           dnf -y builddep mozillavpn.spec
 
       - name: Building package