fix: mypy-errors in helper_script.py (#2763)

[Tengas]

Resolved all but one type-error in helper_script.py

The remaining mypy-error is due to line 264:
cursor = CVEDB.db_open_and_get_cursor(self)
which gives error cve_bin_tool/helper_script.py:262: error: Argument 1 to "db_open_and_get_cursor" of "CVEDB" has incompatible type "HelperScript"; expected "CVEDB" [arg-type]. Later, we also close this connection with CVEDB.db_close(self)

I can think of three ways to resolving this type error:

1. Refactor, either made the affected functions CVEDB.db_open_and_get_cursor() and CVEDB.db_close() static in CVEDB.
2. Inhertiance, we can make Helper_Script a subclass of CVEDB so it will inherit the relevant functions.
3. Repeat the code, we rewrite the relevant parts of db_open_and_get_cursor() and db_close() in the helper_script.py.

[terriko]

Hey, sorry about completely dropping the ball on this pull request. I'm going to update the branch and see if this is still viable to merge.

[codecov-commenter]

Codecov Report

Merging #2873 (8336e52) into main (6d0c925) will decrease coverage by 0.48%.
Report is 1 commits behind head on main.
The diff coverage is 85.71%.

@@            Coverage Diff             @@
##             main    #2873      +/-   ##
==========================================
- Coverage   81.33%   80.86%   -0.48%     
==========================================
  Files         724      724              
  Lines       11347    11348       +1     
  Branches     1544     1544              
==========================================
- Hits         9229     9176      -53     
- Misses       1699     1752      +53     
- Partials      419      420       +1     

Flag	Coverage Δ
longtests	75.59% <85.71%> (-0.01%)	⬇️
win-longtests	78.81% <57.14%> (-0.49%)	⬇️

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Files Changed	Coverage Δ
cve_bin_tool/helper_script.py	82.55% <85.71%> (+0.50%)	⬆️

... and 5 files with indirect coverage changes

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[terriko]

Merge time. Thank you again for your work on this and your extreme patience while it got backburnered for a while!

[Tengas]

No worries, glad it was useful!