tools: exclude libffi changes from test-shared GHA CI

Signed-off-by: Antoine du Hamel <duhamelantoine1995@gmail.com>
PR-URL: #64047
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
Reviewed-By: Filip Skokan <panva.ip@gmail.com>
Reviewed-By: Richard Lau <richard.lau@ibm.com>

Author: aduh95

.github/workflows/test-shared.yml

@@ -22,6 +22,7 @@ on:
       - deps/histogram/**
       - deps/icu-small/**
       - deps/icu-tmp/**
+      - deps/libffi/**
       - deps/llhttp/**
       - deps/merve/**
       - deps/nbytes/**
@@ -73,6 +74,7 @@ on:
       - deps/histogram/**
       - deps/icu-small/**
       - deps/icu-tmp/**
+      - deps/libffi/**
       - deps/llhttp/**
       - deps/merve/**
       - deps/nbytes/**