fix: use vcursor to execute the projection input

[harshit-gangal]

Signed-off-by: Harshit Gangal harshit@planetscale.com

Description

Input to the engine primitive should not be executed directly and should instream use the vcursor primitive functions to execute them as they handle buffering logic if needed.

This PR fixes it for projection primitive for the bug introduced in #10384

Related Issue(s)

Checklist

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