Further isolate environment variables to fix inconsistent results

[prat-man]

When a causal analysis was performed multiple times, the number of experiments considered were different. I found that the issue was due to AWS Lambda instances being reused, which led to some old intermediate files not being deleted, causing erroneous results. I have implemented isolation of executions so each execution will write to a separate directory, thus avoiding any overlaps.

[Copilot]

Pull request overview

This PR addresses inconsistent causal analysis results in AWS Lambda warm starts by isolating filesystem/environment state per invocation, reducing the chance of stale intermediate files being reused across runs.

Changes:

• Introduces per-invocation environment setup in lambda_function.handler() (TMPDIR/TEMP/TMP, HOME/USERPROFILE, MPLCONFIGDIR).
• Switches report outputs to use tempfile.gettempdir() instead of a shared /tmp constant, and removes the TEMP_DIR constant.
• Minor logging fix to print the downloaded filepath.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
lambda_function.py	Adds configure_env() and calls it per invocation to isolate temp/home/MPL config paths.
helper_services/report_helper.py	Writes YAML/PDF/XLSX outputs to the active temp directory (tempfile.gettempdir()).
helper_services/download_helper.py	Adjusts download logging to print the full downloaded filepath.
helper_services/causal_analysis_helper.py	Removes TEMP_DIR/MPLCONFIGDIR initialization tied to the shared temp constant.
common/yaml_to_csv.py	Removes TEMP_DIR/MPLCONFIGDIR initialization tied to the shared temp constant.
common/common_constants.py	Removes the TEMP_DIR constant.

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[AbhinavGor]

@prat-man can you check if this fix is needed?

[prat-man]

@AbhinavGor The fixes are fine. They are not required but will not cause any issues either.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.