openapi-generator [BUG] [go-server] "undefined" string defaults due to unquoted string literal

Bug Report Checklist

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

Description

When using go-server to generate code in v7.2.0+, if a parameter includes a string default, the default value is not rendered in the generated go code with quotes. This leads to the following error when compiling:

out/openapi/go/api_default.go:67:12: undefined: ASC

openapi-generator version

v7.2.0-v7.5.0 and master - has the bug v7.1.0 - doesn't have the bug

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  title: API
  version: 1.0.0
servers:
  - url: https://example.com
paths:
  /foo:
    get:
      parameters:
      - in: query
        name: order
        schema:
          default: ASC
          type: string
      responses:
        "200":
          description: "OK"

Generation Details

Example repository here: https://github.com/chrisjpalmer/openapi-defaults-bug/commit/8b3833273db6eab42e8fb12cea21100d00dd41d5

Expected:

var orderParam string
if query.Has("order") {
	param := query.Get("order")

	orderParam = param
} else {
	param := "ASC"
	orderParam = param
}

Actual:

var orderParam string
if query.Has("order") {
	param := query.Get("order")

	orderParam = param
} else {
	param := ASC
	orderParam = param
}

Steps to reproduce

create a string parameter with a default
generate code with go-server

Related issues/PRs

Can't find any directly related.

Suggest a fix

I believe the bug was introduced here: https://github.com/OpenAPITools/openapi-generator/pull/17321/files#diff-e77c0a7e68c4132e7b3156262b74ee2c92aed8560d1e170ad0df249bc9d5a7fdR515

The solution would be to put quotes around the default value if it is a string... I believe.