fix: support missing dummy row in asc files

[dkrako]

Description

Fixes #917

Implemented changes

• change regex according to support missing dummy row in asc files #917

Type of change

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

How Has This Been Tested?

• add test file eyelink_monocular_no_dummy_example.asc
• add test case to functional/gaze_file_processing_test.py
• add test case to unit/gaze/io/asc_test.py

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (c0c11cd) to head (20da09b).

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #918   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           74        74           
  Lines         3422      3422           
  Branches       613       613           
=========================================
  Hits          3422      3422           

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

[dkrako]

finally I managed to incorporate the example file into the tests.

ready for review @SiQube @prassepaul @senisioi

[SiQube]

I'm not too familiar with this branch of pymovements -- maybe @saeub could review?