Fix removing python class fields on auto-completion

[koxudaxi]

The PR fixes removing python class fields on auto-completion.
The plugin removes fields on auto-completion when reference subclass of pydantic.BaseModel and pydantic.dataclasses.dataclass.
However, a bug works on any class.
It means we can't see class attributes of any class on auto-completion.

[codecov]

Codecov Report

Merging #62 into master will increase coverage by 0.06%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master      #62      +/-   ##
============================================
+ Coverage     79.35%   79.41%   +0.06%     
  Complexity       76       76              
============================================
  Files             7        7              
  Lines           339      340       +1     
  Branches        111      112       +1     
============================================
+ Hits            269      270       +1     
  Misses           20       20              
  Partials         50       50

Impacted Files	Coverage Δ	Complexity Δ
...koxudaxi/pydantic/PydanticCompletionContributor.kt	83.33% <100%> (+0.14%)	1 <0> (ø)	⬇️

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