ci: Fix flatpak deploy enviornment value for Flathub
We typoed the value of FLAT_MANAGER_REPO for flathub deployments in 6a645533
Followup of !2263 (merged)
Part-of: !2373 (merged)
(cherry picked from commit d0110d7f)
We typoed the value of FLAT_MANAGER_REPO for flathub deployments in 6a645533
Followup of !2263 (merged)
Part-of: !2373 (merged)
(cherry picked from commit d0110d7f)