fix: change htsinfer_to_tsv.py exit code

[balajtimate]

Description

When running the htsinfer.smk workflow, the script htsinfer_to_tsv.py exits with exit code 1 when one or more parameters cannot be inferred. Updated it to exit code 0, so the script is ran successfully, even if the inferred metadata is incomplete.
Also modified the table parameters, so if fq1_3p or fq2_3p cannot be inferred, NaN's are added instead of XXXs.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Conventional Commits guidelines

• I made sure the PR title follows the
  https://www.conventionalcommits.org/en/v1.0.0/

Changes to workflow inputs (sample table and/or configs)

• major (add BREAKING CHANGE: in the beginning of the PR title)
  • more fields/properties are required
  • existing ones are dropped entirely
• minor (add feat: in the beginning of the PR title)
  • optional fields/properties are added
  • required ones are made optional

Changes to workflow outputs

• major (add BREAKING CHANGE: in the beginning of the PR title)
  • changes lead to removal/change of existing outputs (format or location)
• minor (add feat: in the beginning of the PR title)
  • additional outputs are generated
  • content (but not format or location) of existing outputs changes

Everything else: patch
(add any other conventional commit in the beginning of the PR title)

Checklist:

• My code changes follow the style of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes
• I have updated the project's documentation