SRC (GWT) and ESL (GWE) do not call write_list()

**Describe the bug**
Based on #2597 and #2598, @mjreno pointed out that both packages (SRC and ESL) need to call write_list().  However, there was some discussion of moving the call to write_list() to the parent class which would precipitate changes in some of the GWF packages, for example (CHD, WEL, and some others).