Add shell check to pre-cmmit hooks & fix issues reported by it (#2579)

run_skyvern.sh

@@ -1,14 +1,15 @@
 #!/bin/bash
 
 pid=$(lsof -t -i :8000)
-if [ ! -z "$pid" ]; then
-  kill $pid
+if [ -n "$pid" ]; then
+  kill "$pid"
 fi
 
 if [ ! -f .env ]; then
   cp .env.example .env
   echo "Please add your api keys to the .env file."
 fi
+# shellcheck source=/dev/null
 source "$(poetry env info --path)/bin/activate"
 poetry install
 ./run_alembic_check.sh