fix(report-converter): Support null column in eslint reports

[SweetVishnya]

ESLint reports may contain bugs with "column": null. Thus, report-converter tool raises an exception:

TypeError: int() argument must be a string, a bytes-like object or a number, not 'NoneType'

We set column number to 0 in such cases.

[SweetVishnya]

@bruntib, can you take a look, please?

[bruntib]

Thanks for the fix! I will approve this change, but could you, please, show an ESLint report where the column number is not available?
This question has two motivations:

• I would just like to make sure that this fix won't hide a potential parser bug of the report converter.
• I would like to test that if it causes any rendering issue in CodeChecker GUI to place a message bubble to a non-existing column number.

Thank you!

[SweetVishnya]

@bruntib, here are some examples:

      {
        "ruleId": "jsdoc/newline-after-description",
        "severity": 2,
        "message": "There must be no newline after the description of the JSDoc block.",
        "line": 38,
        "column": null,
        "nodeType": "Block",
        "endLine": 38,
        "endColumn": null
      },
      {
        "ruleId": "jsdoc/require-description-complete-sentence",
        "severity": 2,
        "message": "Sentence must end with a period.",
        "line": 116,
        "column": null,
        "nodeType": "Block",
        "endLine": 116,
        "endColumn": null
      },
      {
        "ruleId": "jsdoc/check-types",
        "severity": 2,
        "message": "Invalid JSDoc @param \"opt_propertyBag\" type \"Object\"; prefer: \"object\".",
        "line": 233,
        "column": null,
        "nodeType": "Block",
        "endLine": 233,
        "endColumn": null
      },
      {
        "ruleId": "jsdoc/check-tag-names",
        "severity": 2,
        "message": "Invalid JSDoc tag (preference). Replace \"constructor\" JSDoc tag with \"class\".",
        "line": 234,
        "column": null,
        "nodeType": "Block",
        "endLine": 234,
        "endColumn": null
      },