fix(utilities): single session log folder per run via cache in getSessionLogPath

[cs-raj]

Summary

Fixes multiple log folders being created for a single export/import/clone run by caching the session log path for the process. One CLI run now produces one session folder under the configured log path.

Problem

• getSessionLogPath() was called many times per run (Logger constructor ×5, export/import command at end, completeProgressWithMessage per module).
• Each call used new Date() for the folder name (command-YYYYMMDD-HHMMSS-sessionId), so different timestamps created different folders.
• Users saw several session folders (e.g. under log.path/2026-03-02/) for one command, with logs only in the first folder.

Solution

• Cache: In session-path.ts, cache the computed session path in a module-level variable. The first call creates the folder and session.json and caches the path; subsequent calls in the same process return the cached path.
• Tests: Export clearSessionLogPathCache() and call it in beforeEach for the "Session Log Path" and "Session Metadata" tests so each test gets a fresh path and assertions still pass.

Changes

File	Change
cli/packages/contentstack-utilities/src/logger/session-path.ts	Add cachedSessionPath and early return when set; set cache before return; add and export clearSessionLogPathCache().

Behavior

• Export/import/clone: One run → one session folder; all log levels and the final “log stored at” message use the same path.
• Clone (export then import): Same process, same cached path → one folder for the whole clone run.
• Tests: Clearing the cache per test keeps existing expectations valid; Session Log Path and Session Metadata tests pass.

Testing

• pnpm test in cli/packages/contentstack-utilities: Session Log Path and Session Metadata (session.json) tests pass.
• Manual: Run cm:stacks:export with a custom log path; confirm a single session folder is created per run.