flatpak: Operate on a copy of the FlatpakInstallation
This means that global state changes, such as to the no-interaction
flag
of the FlatpakInstallation
, don’t escape outside the context of the
transaction currently being run.
This is a follow up to !283 (merged), using a suggestion by Matthias Clasen.
Signed-off-by: Philip Withnall withnall@endlessm.com