[BUG] [JAVA] [ASCIIDOC] Bug with filtering nulls in examples

[JkbLskw]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• 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?
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Description

Examples in models are always presented despite an existence test. If the element does not exist, null is represented as a value.
The marking of the required fields correctly displays non-existent elements as an empty values.

openapi-generator version

7.0.1

OpenAPI declaration file content or url

A json-example like this

...
"Content": {
  "type": "object",
  "properties": {
	  "content": {
		  "type": "array",
		  "description": "Content of Document in Bytes",
		  "items": {
			  "type": "string",
			  "description": "Content of Document in Bytes",
			  "format": "byte"
		  }
	  }
  },
  "description": "Content of Document"
}
...

with a mustache-template like this

[#{{classname}}]
=== _{{classname}}_ {{title}}

{{unescapedDescription}}

[.fields-{{classname}}]
[cols="2,3,1,2,2"]
|===
| Name| Description| Required| Type| Example

{{#vars}}
| {{baseName}}
| {{description}}
| {{#required}}✓{{/required}}
| {{dataType}} {{#isContainer}} of <<{{complexType}}>>{{/isContainer}}
| {{#example}}{{.}}{{/example}}

{{/vars}}
|===

creates a asciidoc-output like this

[#Content]
=== _Content_ 

Content of Document

[.fields-Content]
[cols="2,3,1,2,2"]
|===
| Name| Description| Required| Type| Example

| content
| Content of Document in Bytes
| 
| List  of <<ByteArray>>
| null

|===

but expected should it be like this

[#Content]
=== _Content_ 

Content of Document

[.fields-Content]
[cols="2,3,1,2,2"]
|===
| Name| Description| Required| Type| Example

| content
| Content of Document in Bytes
| 
| List  of <<ByteArray>>
|

|===