SNOW-1672654 Support for empty encryptionMaterial

[sfc-gh-dstempniak]

Description

If an internal stage is created with SNOWLFAKE_SSE encryption, encryptionMaterial isn't returned from Snowflake.
We need to support empty encryptionMaterial when client side encryption is disabled and isClientSideEncrypted is false.

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 86.28%. Comparing base (5e16693) to head (ee08529).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1048      +/-   ##
==========================================
+ Coverage   86.11%   86.28%   +0.16%     
==========================================
  Files         120      120              
  Lines       11628    11648      +20     
  Branches     1167     1174       +7     
==========================================
+ Hits        10013    10050      +37     
+ Misses       1332     1318      -14     
+ Partials      283      280       -3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.