[PHP] ObjectSerializer fix for array of objects

Created by: alxnegrila

Array of objects translate to map[string,object][] and they fail to deserialize. This is because the deserialization does not parse the mapping string correctly. A quick fix is moving array deserialization before object deserialization.

    ObjectExample:
      type: object
      properties:
        data:
          type: array
          items:
            type: object
            additionalProperties: true

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