ci(e2e): use .env password for db connection

e2e/helpers/db.ts

@@ -2,7 +2,7 @@ import { Pool } from 'pg';
 import { drizzle } from 'drizzle-orm/node-postgres';
 import * as schema from '../../src/server/db/schema';
 
-const connectionString = `postgresql://tipi:postgres@${process.env.SERVER_IP}:5432/tipi?connect_timeout=300`;
+const connectionString = `postgresql://tipi:${process.env.POSTGRES_PASSWORD}@${process.env.SERVER_IP}:5432/tipi?connect_timeout=300`;
 
 const pool = new Pool({
   connectionString,