[BUG] array schemas with single non-object allOf entry aren't resolved

Description

When an array schema contains an allOf definition with just a single element (that is not an object), it is not resolved, even though this can safely be unwrapped. This leads to type resolution errors in generated code. Other composed schemas such as oneOf are handled correctly.

openapi-generator version

v7.22.0

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  title: Test
  version: 1.0.0
paths: {}
components:
  schemas:
    Data:
      type: object
      properties:
        outer:
          type: array
          items:
            allOf:
              - type: array
                items:
                  type: string

Generation Details

It happens with all generated outputs, many languages can't compile the generated code. E.g. go:

// Data struct for Data
type Data struct {
	Outer []Array `json:"outer,omitempty"`
}

Steps to reproduce

run openapi-generator with:
openapi-generator generate -i modules/openapi-generator/src/test/resources/3_0/array_allof_single_type.yaml -o out/ -g <anything>

Related issues/PRs

#23838

Suggest a fix

Basically needs analog handling to the object case:

https://github.com/OpenAPITools/openapi-generator/blob/0b1ac885fba00ee18b839e4e2f51459ce32acc27/modules/openapi-generator/src/main/java/org/openapitools/codegen/InlineModelResolver.java#L328-L335

I'll open a PR

Start with InlineModelResolver.java around lines 328-335, then reproduce using modules/openapi-generator/src/test/resources/3_0/array_allof_single_type.yaml and the openapi-generator generate command. Compare the existing object handling with this single non-object allOf case. Done means the schema is resolved and generated outputs no longer contain the unresolved array type shown in the Go example.