Only do "keys" fixups for non-nested, non-iterable commands (#19408)

## Summary of the Pull Request
When we introduced action IDs, we separated "commands" from
"keybindings", and introduced fixup logic to rewrite the legacy-style
command blocks into the new version. However we don't do any ID logic
for nested and iterable commands, so make sure we don't inform the
loader for fixups in those cases.

## Validation Steps Performed
We no longer repeatedly attempt to fixup the settings file when we see a
`"keys"` entry in a nested/iterable command block

## PR Checklist
- [x] Closes #18736

(cherry picked from commit 04676bd)
Service-Card-Id: PVTI_lADOAF3p4s4AxadtzgfjxUM
Service-Version: 1.23

Author: PankajBhojwani

src/cascadia/TerminalSettingsModel/ActionMapSerialization.cpp

@@ -82,18 +82,13 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
                 command->LogSettingChanges(_changeLog);
                 AddAction(*command, keys);
 
-                if (jsonBlock.isMember(JsonKey(KeysKey)))
-                {
-                    // there are keys in this command block meaning this is the legacy style -
-                    // inform the loader that fixups are needed
-                    _fixupsAppliedDuringLoad = true;
-                }
-
-                if (jsonBlock.isMember(JsonKey(ActionKey)) && !jsonBlock.isMember(JsonKey(IterateOnKey)) && origin == OriginTag::User && !jsonBlock.isMember(JsonKey(IDKey)))
+                if (jsonBlock.isMember(JsonKey(ActionKey)) && !jsonBlock.isMember(JsonKey(IterateOnKey)) && origin == OriginTag::User &&
+                    (!jsonBlock.isMember(JsonKey(IDKey)) || jsonBlock.isMember(JsonKey(KeysKey))))
                 {
                     // for non-nested non-iterable commands,
-                    // if there's no ID in the command block we will generate one for the user -
-                    // inform the loader that the ID needs to be written into the json
+                    // if there's no ID in the command block we will generate one for the user,
+                    // or if there are keys in this command block that means this is the legacy style -
+                    // in either case, inform the loader that fixups are needed
                     _fixupsAppliedDuringLoad = true;
                 }
             }