fix(Dashboard): Exclude edit param in async screenshot

[geido]

SUMMARY

This PR #30675 introduced a way to pass urlParams to the async dashboard screenshot generation endpoint. However, edit was an acceptable value which caused the system to take a screenshot in edit mode of a newly created dashboard. This PR fixes that.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N.A.

TESTING INSTRUCTIONS

1. Create a new dashboard
2. Download the dashboard screenshot as PDF
3. The screenshot should not be showing the dashboard in edit mode

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags: ENABLE_DASHBOARD_SCREENSHOT_ENDPOINTS ENABLE_DASHBOARD_DOWNLOAD_WEBDRIVER_SCREENSHOT
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[Vitor-Avila]

Thanks for catching and fixing this! 🙏