Add missing k-* legacy sampler names to init file migrate list (#3625)

The `invokeai-configure` script migrates the old invokeai.init file to
the new invokeai.yaml format. However, the parser for the invokeai.init
file was missing the names of the k* samplers and was giving a parser
error on any invokeai.init file that referred to one of these samplers.
This PR fixes the problem.

Ironically, there is no longer the concept of the preferred scheduler in
3.0, and so these sampler names are simply ignored and not written into
`invokeai.yaml`

invokeai/backend/install/legacy_arg_parsing.py

@@ -4,6 +4,8 @@ import argparse
 import shlex
 from argparse import ArgumentParser
 
+# note that this includes both old sampler names and new scheduler names
+# in order to be able to parse both 2.0 and 3.0-pre-nodes versions of invokeai.init
 SAMPLER_CHOICES = [
     "ddim",
     "ddpm",
@@ -27,6 +29,15 @@ SAMPLER_CHOICES = [
     "dpmpp_sde",
     "dpmpp_sde_k",
     "unipc",
+    "k_dpm_2_a",
+    "k_dpm_2",
+    "k_dpmpp_2_a",
+    "k_dpmpp_2",
+    "k_euler_a",
+    "k_euler",
+    "k_heun",
+    "k_lms",
+    "plms",
 ]
 
 PRECISION_CHOICES = [