SNOW-1418500: Add side effect to _resolve_packages

[sfc-gh-aalam]

1. Which Jira issue is this PR addressing? Make sure that there is an accompanying issue to your PR.

   Fixes SNOW-1418500

2. Fill out the following pre-review checklist:

   • I am adding a new automated test(s) to verify correctness of my new code
     • If this test skips Local Testing mode, I'm requesting review from @snowflakedb/local-testing
   • I am adding new logging messages
   • I am adding a new telemetry message
   • I am adding new credentials
   • I am adding a new dependency
   • If this is a new feature/behavior, I'm adding the Local Testing parity changes.

3. Please describe how your code solves the related issue.

   We rely on side effect of _resolve_pacakges to add update attribute _packages to add packages https://github.com/snowflakedb/snowflake/blob/main/ExecPlatform/src/coprocessor/python/PythonStoredProcSession.cpp#L106-L111.

In this change, we apply the side effect i.e. update existing_packages_dict or _packages once the packages have been resolved.

[sfc-gh-aalam]

https://ci-dev-142.int.snowflakecomputing.com/job/PythonStoredProcBuildPrecommitTest/1281/

[sfc-gh-jrose]

Is this more or less a reversion of your previous change?

[sfc-gh-aalam]

Is this more or less a reversion of your previous change?

It not a complete reversion. In this PR we are only reverting part which was remove side effects from _resolve_packages. We still make a copy of _packages dict that was passed into and update it in a single step instead of updating it all throughout the function.