Added SnowflakeDbDataReader implementation of GetEnumerator using DbEnumerator class

[sfc-gh-jmartinezramirez]

Description

Added implementation of GetEnumerator using DbEnumerator class.

Checklist

• Code compiles correctly
• Code is formatted according to Coding Conventions
• Created tests which fail without the change (if possible)
• All tests passing (dotnet test)
• Extended the README / documentation, if necessary
• Provide JIRA issue id (if possible) or GitHub issue id in PR name

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.89%. Comparing base (3d0194c) to head (408dc90).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1031      +/-   ##
==========================================
+ Coverage   85.86%   85.89%   +0.02%     
==========================================
  Files         118      118              
  Lines       11456    11455       -1     
  Branches     1146     1146              
==========================================
+ Hits         9837     9839       +2     
+ Misses       1335     1333       -2     
+ Partials      284      283       -1     

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