fix: event listener leak in helper.js - #7975

Description

This pr fixes an event listener leak in planet/js/helper.js.

Each time hideOnClickOutside() was called for the same anchor element it added a new document click listener without removing the previous one, due to this duplicate listeners stacked unnecessarily.

I added a module scoped WeakMap to track the active listener for each anchor element.
Before adding a new listener, the existing one is removed which ensure only one outside click listener exists per anchor at a time.

PR Category

• Bug Fix — Fixes a bug or incorrect behavior
• Feature — Adds new functionality
• Performance — Improves performance (load time, memory, rendering, etc.)
• Tests — Adds or updates test coverage
• Documentation — Updates to docs, comments, or README
• Chore / Refactor — Maintenance, cleanup, or refactoring with no behavior change
• CI/CD — Changes to CI/CD workflows and automation

Testing Performed

Before: repeatedly opening and closing the share boxes kept adding new document click listeners

After: listener count consistently stayed at the baseline

Additional Notes for Reviewers

• The baseline of three document click listeners on initial page load is expected and comes from existing application initialization (materialize css and core tab handlers)
• The WeakMap garbage collection ensures memory safety when DOM elements are removed.