The good news on this is all the pipes for the gas are at the top behind the plastic housing in the roof of the freezer.
So what has happened here wont cause no damaged what so ever. What you can do is get some silicon seleant and fill the hole with sealent and that will be just fine like that.
It wont effect the working what so ever on this so cover the hole with silicon seleant and it will be fine from there.
If you need anymore info just get back to me.
I just use food grade sealent as that does the trick. As its going into the freezer so has to be food safe sealent.
But it will set and be fine at -18 degrees anyway.
You can get it from the likes of B&Q or Wickes as they will sell it.
If you could remember to rate the answer that would be great.