Refactor: llama-impl.h should be private

[mofosyne]

Background Description

First highlighted: #11596

Initial PR: #11617

slaren suggests a better fix #11617 (comment)

Possible Refactor Approaches

target_include_directories(llama PUBLIC . ../include ../common) 

Should be set to private according to slaren

[github-actions]

This issue was closed because it has been inactive for 14 days since being marked as stale.