[Lists]: list(empty) delete values will be panic about agones

[GStones]

Already resolved: #3606.
patch：func deleteValues should check capacity <0 to keep code security

[igooch]

Thanks for the fix, although I'm surprised the list not containing the value to delete wasn't caught earlier in the code

agones/pkg/sdkserver/sdkserver.go

Line 1177 in e88f7c5

return nil, errors.Errorf("not found. Value: %s not found in List: %s", in.Value, in.Name)

. How are you calling the list delete?

[GStones]

This panic happend before this PR(#3606).
updateList not clear, every loop will delete from list