chore: implement twilio-external-task Lambda [CHI-3955]

[gpaoloni]

This PR implements the Lambda introduced by https://github.com/techmatters/infrastructure-config/pull/588.

Description

This PR implements twilio-external-task:

• The implementation follows the same idea as account-scoped Lambda, but instead of account sid it relies on account short code.
• Auth is done via static API key.
• If valid, creates a new external_task channel type task in the target Twilio account.

Example request:

❯ curl -X POST 'https://hrm-development.tl.techmatters.org/lambda/twilio/external-task/as' -H "Authorization: Basic < external_task_api_key >" -H "Content-Type:
application/json" -H "Accept: application/json" -d '{"key": "test-external-id" }'

where external_task_api_key is the SSM parameter that corresponds to the AS development account sid.

Configuration

To test the integration, other than applying the linked PR in infra and deploying this code

• Add SSM /<environment>/twilio/<account_sid>/external_task_api_key parameter. Make sure is only number (lower and upper case) and numbers. E.g. /development/twilio/ACd8a2e89748318adf6ddff7df6948deaf/external_task_api_key
• In Twilio
  • Create external channel type.
  • Edit workflow expressions to match external tasks.
  • [OPTIONAL] Add custom task queue.

Checklist

• Corresponding issue has been opened
• New tests added
• Feature flags added
• Strings are localized
• Tested for chat contacts
• Tested for call contacts

Other Related Issues

None

Verification steps

AFTER YOU MERGE

1. Cut a release tag using the Github workflow. Wait for it to complete and notify in the #aselo-deploys Slack channel.
2. Comment on the ticket with the release tag version AND any additional instructions required to configure an environment to test the changes.
3. Only then move the ticket into the QA column in JIRA

You are responsible for ensuring the above steps are completed. If you move a ticket into QA without advising what version to test, the QA team will assume the latest tag has the changes. If it does not, the following confusion is on you! :-P

[stephenhand]

Might be better to move this call out of the try / catch block so we don't get misleading 403s for a configuration issue?