ci: restrict swagger code purging to own files

[michaeladler]

Description

Currently everything except for the ent directory is removed. This does not scale when adding more generated code. Instead, the swagger task should only purge its own files (before recreating them).

Issues Addressed

List and link all the issues addressed by this PR.

Change Type

Please select the relevant options:

• Bug fix (non-breaking change that resolves an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist

• I have read the CONTRIBUTING document.
• My changes adhere to the established code style, patterns, and best practices.
• I have added tests that demonstrate the effectiveness of my changes.
• I have updated the documentation accordingly (if applicable).
• I have added an entry in the CHANGELOG to document my changes (if applicable).

[codecov]

Codecov Report

Merging #42 (4647643) into main (53a9b5f) will not change coverage.
Report is 4 commits behind head on main.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main      #42   +/-   ##
=======================================
  Coverage   77.66%   77.66%           
=======================================
  Files          79       79           
  Lines        3027     3027           
=======================================
  Hits         2351     2351           
  Misses        497      497           
  Partials      179      179