fix: overriding classes from lutaml type not working

[HassanAkbar]

This PR fixes the issue of the overrided methods in the inherited classes from Lutaml::Model::Type not working.

closes #224, closes #199

[HassanAkbar]

@ronaldtse,
lutaml/reqif#1 should be solvable now as to_xml will be called for HighPrecisionDateTime after this fix.

[HassanAkbar]

@ronaldtse, there are specs from genericode that are failing in this PR.
The reason is the mapping of the XML as follows:

      <Row>
         <Value ColumnRef="code">
            <SimpleValue>10</SimpleValue>
         </Value>
         <Value ColumnRef="name">
            <SimpleValue>group</SimpleValue>
         </Value>
         <Value ColumnRef="description">
            <SimpleValue>A unit of count defining the number of groups (group: set of items classified together).</SimpleValue>
         </Value>
         <Value ColumnRef="levelcategory">
            <SimpleValue>3.9</SimpleValue>
         </Value>
      </Row>

In the above example XML, the mapping of ColumnRef in a Value should be to a String, Instead, it is to a class ColumnRef which has the following definition:

class ColumnRef < Lutaml::Model::Serializable
    attribute :id, :string
    attribute :external_ref, :string
    attribute :use, :string
    attribute :annotation, Annotation
    attribute :canonical_version_uri, :string
    attribute :location_uri, :string, collection: true
    attribute :data, DataRestrictions

    xml do
      root "ColumnRef"
      namespace "http://docs.oasis-open.org/codelist/ns/genericode/1.0/", "gc"

      map_attribute "Id", to: :id
      map_attribute "ExternalRef", to: :external_ref
      map_attribute "Use", to: :use
      map_element "Annotation", to: :annotation, prefix: nil, namespace: nil
      map_element "CanonicalVersionUri", to: :canonical_version_uri, prefix: nil, namespace: nil
      map_element "LocationUri", to: :location_uri, prefix: nil, namespace: nil
      map_element "Data", to: :data, prefix: nil, namespace: nil
    end
  end

So as per the change in our PR:

We are now calling from_#{format} to support deserialization using the override methods. But when from_#{format} is called on ColumnRef, It breaks since the value is a string i.e “description” but the type is ColumnRef that should be deserialized using its own attributes but the code breaks.

Please let me know what should we do in this case