fix: sessions playwright traces - naming convention and error handling

[kobenguyent]

This PR fixes session-related issues in the Playwright helper:

Issues Fixed:

1. Naming Convention: Changed session artifact naming from ${test.title}_${sessionName} to ${sessionName}_${test.title} to prevent file collisions when test titles are truncated
2. Tracing Errors: Added graceful error handling for "Must start tracing before stopping" errors in session contexts
3. Main Session Processing: Fixed duplicate main session processing by excluding empty session names

Changes Made:

• lib/helper/Playwright.js: Updated _failed() and _passed() methods with improved session handling
• test/helper/Playwright_test.js: Added comprehensive tests covering all fix scenarios

Testing:

• ✅ All 4 new session tests pass
• ✅ Validates proper naming convention
• ✅ Tests error handling for invalid contexts
• ✅ Ensures main session isn't duplicated

Related to issue: Session/Playwright traces naming convention and error handling improvements.