What this PR does / why we need it:

I spotted this issue with a task that ran the AWS CLI to create DynamoDB tables. The output of the command is in JSON. When the output is JSON it comes into garden as an object, which doesn't have a trim method. You can see this in run.ts.

You can recreate this issue by having a task output JSON, ala.

#!/usr/bin/env bash

# Forced for the sake of the test.
echo '{"hello": "world"}'
exit 0

setup.sh

kind: Module
name: database-tables
description: Create database tables
type: container
tasks:
 - name: db-migrate-default
   command: ["bash", "/project/setup.sh"]
   dependencies:
     - database-default

garden.yml

and then a docker file that just copies over the setup.sh file.

Which issue(s) this PR fixes:

Internal issue at the company I work for

Special notes for your reviewer: