chore: build.sh script unnecessarily requires lerna to be globally in…

…stalled (aws#24217)

Either lerna needs to be installed as a dependency or run through npx. Otherwise build.sh fails in the middle of a build on a system without it installed.

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build.sh

@@ -86,7 +86,7 @@ concurrency=$(node -p 'Math.max(1, require("os").cpus().length - 1)')
 
 echo "============================================================================================="
 echo "building..."
-time lerna run $bail --stream --concurrency=$concurrency $runtarget || fail
+time npx lerna run $bail --stream --concurrency=$concurrency $runtarget || fail
 
 if [ "$check_compat" == "true" ]; then
   /bin/bash scripts/check-api-compatibility.sh