tax_return: fix allowed content types, Tax Return does not exist

bt5/erp5_tax_return/PortalTypeAllowedContentTypeTemplateItem/allowed_content_types.xml

 <allowed_content_type_list>
  <portal_type id="Tax Return Module">
-  <item>Tax Return</item>
+  <item>Sample Tax Return</item>
  </portal_type>
  <portal_type id="Tax Return Type">
   <item>Action Information</item>

bt5/erp5_tax_return/bt/template_portal_type_allowed_content_type_list

-Tax Return Module | Tax Return
+Tax Return Module | Sample Tax Return
 Tax Return Type | Action Information
 Tax Return Type | Role Information
 Tax Return Type | Tax Return Line
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