Simplify the test section of the PR Template

[toupper]

Description

📄 Summary

This PR updates the Pull Request template to simplify and clarify the testing section.

🧩 Changes

• Replaced the three previous sections:
  • ## Steps to reproduce
  • ## Testing information
• Introduced a single unified section:
  • ## Test Steps

🧠 Rationale

The goal is to make the testing section clearer and more flexible for all PR types.
“Test Steps” encourages authors to describe how to validate their changes (or the intended workflow) without unnecessary duplication or over-specificity.
This helps reviewers focus on what truly matters for verification.

✅ Example

### Test Steps
1. Launch the app and log in with a valid site.
2. Navigate to the POS Orders screen.
3. Verify that orders load correctly and the pull-to-refresh behaves as expected.

• I have considered if this change warrants release notes and have added them to RELEASE-NOTES.txt if necessary. Use the "[Internal]" label for non-user-facing changes.