Keygen workflow remove pull request action trigger

[danidrasovean]

Reasoning behind the pull request

• Building the Docker image for keygenerator on each pull request is not necessary.

Proposed changes

• Removed the pull request trigger from the GitHub Actions workflow, leaving only the manual workflow_dispatch trigger active.

Testing procedure

Pre-requisites

Based on the Contributing Guidelines the PR author and the reviewers must check the following requirements are met:

• was the PR targeted to the correct branch?
• if this is a larger feature that probably needs more than one PR, is there a feat branch created?
• if this is a feat branch merging, do all satellite projects have a proper tag inside go.mod?

[github-actions]

📊 MultiversX Automated Test Report: View Report

🔄 Build Details:

• mx-chain-go Commit Hash: aa637404027f90235b07253691372c9cad644c63
• Current Branch: keygen-remove-pull-request-action-trigger
• mx-chain-go Target Branch: rc/v1.7.next1
• mx-chain-simulator-go Target Branch: rc/v1.7.next1
• mx-chain-testing-suite Target Branch: rc/v1.7.next1

🚀 Environment Variables:

• TIMESTAMP: 26082024-122117
• PYTEST_EXIT_CODE: 0
  🎉 MultiversX CI/CD Workflow Complete!