fix show-json test to expect error from nested mod

One of the show json command tests expected no error when presented with
an invalid configuration in a nested module. Modify the test created in
PR #21569 so that it can still verify there is no panic, but now expect
an error from init.

command/testdata/show-json/nested-module-error/modules/more-modules/main.tf

@@ -0,0 +1,4 @@
+variable "misspelled" {
+  default     = "ehllo"
+  descriptoni = "I am a misspelled attribute"
+}