[ENH] Update subworkflow preproc_t1

[anroy1]

Type of improvement

• Documentation
• Development tools (e.g. linter, formatter, etc.)
• Development container
• Global update (please specify)
• Other (please specify)

Describe your improvement

• Adding .map() function to input channel structure to correctly manage empty optional channels
• Removing the ants BET checks (template and probability map)

Checklist before requesting a review

• Ensure the syntax is correct (EditorConfig and Prettier must pass)
• Run the test suites if your changes affect any module
• Regenerate the Poetry lock file if you have updated the dependencies
• Ensure the documentation is up-to-date

[AlexVCaron]

Closes AlexVCaron#11

[AlexVCaron]

All good on my end @arnaudbore should we have a discussion on optional input definition on beginning next week ?

[arnaudbore]

GTG

[AlexVCaron]

I will add the comments on the joins with remainders in a separate PR