Remove FF ci_trigger_forward_variables

What does this MR do and why?

This MR removes the FF ci_trigger_forward_variables.

• Feature issue: #213729 (closed)
• Feature flag issue: #355572 (closed)
• Introduced in: !82676 (merged)
• Improved in: !84478 (merged)
• Enabled by default in 14.10: !85263 (merged)

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