Modules meta.yml differentiate between tuple and single element channels

[mirpedrol]

Description of the bug

With the restructuring of the modules meta.yml files, we introduced an extra level of indentation to account for tuple channels. However, channels that are not tuples shouldn't be indented.

This must be fixed in:

• The module template
• When running nf-core modules lint with the --fix argument
• In the website when showing the inputs and outputs of modules
• The JSON schema from nf-core/modules must be updated
• All modules meta.yml must be fixed (can be done with a bulk PR by running nf-core modules lint --fix --all)

Command used and terminal output

No response

System information

No response