[Up-port] check if order data is available to incl ec

[torhoehn]

Description

Original pull request: #15765

Fixed Issues (if relevant)

1. Google analytics pageview being triggered twice #12221: Google analytics pageview being triggered twice (see comment Google analytics pageview being triggered twice #12221 (comment))

Manual testing scenarios

1. Created a Google Analytics test account
2. Order something
3. Order will appear in Google Analytics (Conversion -> E-Commerce) or see console with running Google Analytics Debugger (https://chrome.google.com/webstore/detail/google-analytics-debugger/jnkmfdileelhofjcijamephohjechhna). Transfered data will contain product specific data.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @torhoehn. Thank you for your contribution.
Changes from your Pull Request will be available with the upcoming 2.3.0 release.