Option --keep-sensors-on-exit doesn't work with disabling/enabling policies

[mtardy]

I think I bumped into an unexpected thing while fixing the memory use of disabled policies.

If you use the --keep-sensors-on-exit, then when you use tetra tp disable <policy-name>, you trigger .Unload() on the program which is expecting mostly to be called on exit it seems since we don't unpin the progs if option.Config.KeepSensorsOnExit is here.

tetragon/pkg/sensors/unloader/unloader.go

Lines 59 to 65 in 61b575c

	func (pu PinUnloader) Unload() error {
	defer pu.Prog.Close()
	if !option.Config.KeepSensorsOnExit {
	return pu.Prog.Unpin()
	}
	return nil
	}

Thus you didn't disable the policy, so --keep-sensors-on-exit doesn't work currently with the enable/disable feature.

cc @olsajiri