Take the field label into account for entity references

Every entity reference is currently labeled as Resource Identifier in the json schema, see

        revision_uid: {
          type: 'object',
          properties: {
            data: {
              type: 'object',
              required: ['type', 'id'],
              properties: {
                type: {
                  type: 'string',
                  title: 'Referenced resource',
                  enum: ['user--user'],
                },
                id: {
                  type: 'string',
                  title: 'Resource ID',
                  format: 'uuid',
                  maxLength: 128,
                },
              },
            },
          },
          title: 'Resource Identifier',

as example

It would be nice to actually have the field label used here