[BUG] Asciidoc generate wrong null table cell value

[vigarpad]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Asciidoc generator generate wrong cell value in adoc, when the cell is empty!

openapi-generator version

7.17.0

OpenAPI declaration file content or url

      parameters:
        - name: applicantId
          in: path
          description: The unique identifier of the applicant
          required: true
          schema:
            type: string
            format: uuid

Generation Details

Generate wrong asciidoc table:

'''adoc
===== Parameters

====== Path Parameters

[cols="2,3,1,1,1"]
|===
|Name| Description| Required| Default| Pattern

| applicantId
| The unique identifier of the applicant
| X
| null
| |===

'''

Correct asciidoc table:

'''adoc
===== Parameters

====== Path Parameters

[cols="2,3,1,1,1"]
|===
|Name| Description| Required| Default| Pattern

| applicantId
| The unique identifier of the applicant
| X
| null
|
|===

'''

Steps to reproduce

Related issues/PRs

Suggest a fix