fix: Dio error holds a reference to null values

[Nidal-Bakir]

When an error occurs, the Dio error object could hold null properties causing the error (Type 'Null' is not a subtype of type 'Object')

New Pull Request Checklist

• I am not disclosing a vulnerability.
• I am creating this PR in reference to an issue.

Issue Description

Closes: #774

Approach

Add null aware operator ??:

on dio.DioError catch (error) {
      return ParseNetworkResponse(
        data: error.response?.data ?? _fallbackErrorData,
        statusCode: error.response?.statusCode ?? ParseError.otherCause,
      );
    }

TODOs before merging

All set

• Add tests
• Add changes to documentation (guides, repository pages, in-code descriptions)
• A changelog entry

[parse-github-assistant]

I will reformat the title to use the proper commit message syntax.

[parse-github-assistant]

Thanks for opening this pull request!

[mbfakourii]

Thanks for checking nulls, looks good

[mtrezza]

Could you add a changelog entry using the PR title and bump the version? See existing entries for examples.

Lint also needs some changes.

[codecov]

Codecov Report

Base: 15.88% // Head: 15.82% // Decreases project coverage by -0.07% ⚠️

Coverage data is based on head (69e3a1b) compared to base (b07ce8c).
Patch coverage: 0.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #825      +/-   ##
==========================================
- Coverage   15.88%   15.82%   -0.07%     
==========================================
  Files          47       47              
  Lines        2865     2876      +11     
==========================================
  Hits          455      455              
- Misses       2410     2421      +11     

Impacted Files	Coverage Δ
...ackages/dart/lib/src/network/parse_dio_client.dart	0.00% <0.00%> (ø)

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[mtrezza]

Looks good! Waiting for CI to pass...