fix(dashboard): enable dashboard's "Save as" menu option for all users

[raymondtieu]

SUMMARY

• Removed the RBAC feature flag and user type checks in when checking canUserSaveAsDashboard permissions
• Allow all users to use the "Save as" menu option in a dashboard

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

• Open a dashboard as a non-admin and non-owner, "Save as" should be available on every dashboard

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• 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

[github-actions]

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