fix: event listener leak in helper.js

[Jetshree]

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.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 62.06%. Comparing base (5462731) to head (5833ac0).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7975      +/-   ##
==========================================
+ Coverage   62.05%   62.06%   +0.01%     
==========================================
  Files         187      187              
  Lines       58377    58394      +17     
==========================================
+ Hits        36227    36244      +17     
  Misses      22150    22150              

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