[BUG][JAVA][resttemplate] 5.0.0-beta - missing import of HttpBearerAuth in ApiClient

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

openapi-generator version

5.0.0-beta
It is a regression. 4.3.1 worked fine.

OpenAPI declaration file content or url

paths:
 /foo:
  get:
     security:
        - testAuth: []

components:
  securitySchemes:
    testAuth:
      type: http
      scheme: TEST
      in: header

Command line used for generation

<generatorName>java</generatorName>
<library>resttemplate</library>
<generateApis>true</generateApis>
<generateApiDocumentation>true</generateApiDocumentation>
<generateApiTests>false</generateApiTests>
<generateModels>true</generateModels>
<generateModelDocumentation>false</generateModelDocumentation>
<generateModelTests>false</generateModelTests>
<generateSupportingFiles>true</generateSupportingFiles>

Steps to reproduce

OpenAPI declaration needs to have securitySchemes with http auth.
After openapi-generator-maven-plugin generates classes, maven-compiler-plugin fails to compile class ApiClient.
It says that symbol HttpBearerAuth is not found.
ApiClient is missing import of HttpBearerAuth. This class is in "auth" subpackage.

The compilation error is in generated ApiClient class on the following line:

authentications.put("testAuth", new HttpBearerAuth("TEST"));

Related issues/PRs

Suggest a fix

Add import to HttpBearerAuth in ApiClient if HTTP auth is used.

Start by inspecting the Java RestTemplate generator templates and the generated ApiClient import section, then reproduce the Maven compilation failure with the provided OpenAPI security scheme. Done means generated ApiClient compiles when HTTP authentication creates HttpBearerAuth from the auth subpackage, while existing generation behavior remains intact.