[BUG] [DefaultGenerator] Multi tags Webhooks generation overwrite generated API file

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?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

When webhooks are defined with multiple tags, and a tag is shared with a "normal" API, the webhook [by tag] file generation is overwriting the just generated >API file with same tag.

So after API file was created with operations related to path described by OAS file, content is overwritten with the operation related to the webhooks definition because of Webhooks is also having the sametag value : it create same file name

openapi-generator version

master branch (commit #74044c3427)

OpenAPI declaration file content or url

gist: link

Generation Details

java -jar ./modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -i foo-multiTagsAndWebhooks.yaml -g java -o output --additional-properties=library=apache-httpclient

Steps to reproduce

Execute the generation based onto above command line options

Related issues/PRs

Suggest a fix

Issue is coming from sequence (https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java#L1304-L1309):

        // apis
        List<OperationsMap> allOperations = new ArrayList<>();
        generateApis(files, allOperations, allModels);
        // webhooks
        List<WebhooksMap> allWebhooks = new ArrayList<>();
        generateWebhooks(files, allWebhooks, allModels);

Start with the generateApis and generateWebhooks calls in modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java around lines 1304-1309. Run the provided Java generation command with the linked foo-multiTagsAndWebhooks.yaml reproduction, then inspect the generated API file. Done means webhook generation no longer overwrites the API generated for a shared tag.