Broken completion for allof inside ref

Describe the bug

Expected Behavior

Completion returns key:\n\t

Current Behavior

Completion returns key

Steps to Reproduce

1. Insert # yaml-language-server: $schema=example.schema.json as file header
2. Try a working example and observe expected behavior:

{
  "title": "Values",
  "type": "object",
  "$schema": "http://json-schema.org/schema#",
  "$ref": "#/$defs/instance",
  "required": [
    "thisinstance"
  ],
  "$defs": {
    "union": {
      "type": "object",
      "properties": {
        "config0": {
          "type": "string"
        }
      }
    },
    "instance": {
      "type": "object",
      "properties": {
        "thisinstance": {
          "$ref": "#/$defs/union"
        }
      }
    }
  }
}

3. Try a broken example and observe undesired behavior

{
  "title": "Values",
  "type": "object",
  "$schema": "http://json-schema.org/schema#",
  "$ref": "#/$defs/instance",
  "required": [
    "thisinstance"
  ],
  "$defs": {
    "union": {
      "allOf": [
        {
          "type": "object",
          "properties": {
            "config0": {
              "type": "string"
            }
          }
        },
        {
          "type": "object",
          "properties": {
            "config1": {
              "type": "string"
            }
          }
        }
      ]
    },
    "instance": {
      "type": "object",
      "properties": {
        "thisinstance": {
          "$ref": "#/$defs/union"
        }
      }
    }
  }
}

Environment

• Linux

Reproduce the completion behavior using the schema examples and the YAML language-server schema header described in the issue. Completion should return key:\n\t for the allOf-inside-$ref case, matching the working example rather than returning only key.