linting: capture correct error for invalid .nf-core.yml

[mashehu]

Closes #3573

New error output (e.g. for scnanoseq) is

ERROR    Config file '.nf-core.yml' is invalid
         lint.pipeline_todos: Input should be a valid boolean
         Got instead: ['README.md', 'main.nf']

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 77.81%. Comparing base (9df2b3b) to head (0088e00).

Files with missing lines	Patch %	Lines
nf_core/commands_modules.py	0.00%	1 Missing ⚠️

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.