Workflow: Exclude OpenAPI folder from Webapp QA workflow

[GODrums]

Motivation

We want to avoid unnecessary workflow executions by limiting its trigger conditions.

Description

This PR excludes the OpenAPI auto-generated folder from the trigger conditions for the workflow. In cases where changes in the application server require a OpenAPI Spec re-generation, this workflow should not be needed.

Both ESLint and Prettier are configured to ignore the openapi folder, so a workflow execution is redundant and should be guaranteed to not provide any new results.

Checklist

General

• [x] PR title is clear and descriptive
• [x] PR description explains the purpose and changes
• [x] Code follows project coding standards
• [x] Self-review of the code has been done
• [ ] Changes have been tested locally