Fix filtering skill up doc

[vinnamkim]

Summary

• There was a mistake and this PR fixes it by removing duplicated filter_func().

How to test

Checklist

• I have added unit tests to cover my changes.​
• I have added integration tests to cover my changes.​
• I have added the description of my changes into CHANGELOG.​
• I have updated the documentation accordingly

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.
• I have updated the license header for each file (see an example below).

# Copyright (C) 2023 Intel Corporation
#
# SPDX-License-Identifier: MIT

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (fb7b6f9) 80.45% compared to head (d3f15e6) 80.49%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1238      +/-   ##
===========================================
+ Coverage    80.45%   80.49%   +0.03%     
===========================================
  Files          268      269       +1     
  Lines        29968    29991      +23     
  Branches      5856     5856              
===========================================
+ Hits         24112    24140      +28     
+ Misses        4490     4487       -3     
+ Partials      1366     1364       -2     

Flag	Coverage Δ
ubuntu-20.04_Python-3.8	80.47% <ø> (?)
windows-2022_Python-3.8	80.45% <ø> (ø)

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