foot: set OOMPolicy=continue for foot server (#2749)

Previously, if a process inside a foot client triggered the OOM killer,
systemd would also kill the parent unit, namely the foot server.
This is not ideal if a user has a lot of clients attached, and it's
usually not the terminal emulator's fault that a process inside it has
ended up using all the available memory.

modules/programs/foot.nix

@@ -71,6 +71,7 @@ in {
         Service = {
           ExecStart = "${cfg.package}/bin/foot --server";
           Restart = "on-failure";
+          OOMPolicy = "continue";
         };
 
         Install = { WantedBy = [ "graphical-session.target" ]; };

tests/modules/programs/foot/systemd-user-service-expected.service

@@ -3,6 +3,7 @@ WantedBy=graphical-session.target
 
 [Service]
 ExecStart=@foot@/bin/foot --server
+OOMPolicy=continue
 Restart=on-failure
 
 [Unit]