Remove toList() channel operation from inside onComplete block

[robsyme]

This PR resolves an important bug in the nf-core template, whereby all workflows will hang if the --email parameter is supplied.

The onComplete block will hang if there are any (queue) channel operations inside the block. All values in the onComplete block must be resolved to single values or value channels before the onComplete block starts.

The async channels are not available inside onComplete, so calling the toList() operation will hang forever as the async queue channel will never be completed.

PR checklist

• [ ] This comment contains a description of changes (with reason)
• [ ] CHANGELOG.md is updated
• [ ] If you've fixed a bug or added code that should be tested, add tests!
• [ ] Documentation in docs is updated

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 75.80%. Comparing base (1dd8ea0) to head (71410fd).

Additional details and impacted files

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.