[BUG][Kotlin] Kotlin generator ignores apiNameSuffix and uses legacy configOptions.apiSuffix instead

[manujell73]

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

apiNameSuffix setting gets ignored when using generatorName = "kotlin"
It does use the configOption apiSuffix.

openapi-generator version

7.22.0

OpenAPI declaration file content or url

Not really any specific file content, just overall Kotlin Api generation

Generation Details

I am using the gradle plugin but this would be the important stuff in the yaml format:

generatorName: kotlin
apiNameSuffix: CustomApi

Steps to reproduce

1. Configure OpenAPI Generator with generatorName: kotlin.
2. Set apiNameSuffix: CustomSuffix.
3. Generate code.
4. Generated API class names use default Api suffix.
5. Set additionalProperties.apiSuffix: CustomSuffix and regenerate.
6. Generated API class names now use the CustomSuffix.

Related issues/PRs

apiSuffix Kotlin implementation: #2690
apiNameSuffix global implementation: #3918

Suggest a fix

I will open a PR, but here is a description:
Remove the Kotlin specific apiSuffix property and use the global apiNameSuffix instead.
Change inside AbstractKotlinCodegen.java line 764.

Since the fix is breaking I will open the PR to the 8.0.x branch

[manujell73]

I also noticed that the apiNamePrefix property also does not get used for the kotlin generation.