refactor: rewrite mergeRefs in typescript

[adamalston]

Closes N/A

Rewrote mergeRefs in TypeScript.

Changelog

New

• Added testing for mergeRefs.

Changed

• Rewrote mergeRefs in TypeScript.

Testing / Reviewing

Do we need both useMergedRefs and mergeRefs, or should we keep only one?

PR Checklist

As the author of this PR, before marking ready for review, confirm you:

• Reviewed every line of the diff
• Updated documentation and storybook examples
• Wrote passing tests that cover this change
• Addressed any impact on accessibility (a11y)
• Tested for cross-browser consistency
• Validated that this code is ready for review and status checks should pass

More details can be found in the pull request guide

[codecov]

Codecov Report

❌ Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.80%. Comparing base (30b4f87) to head (99f75dd).
⚠️ Report is 200 commits behind head on main.

Files with missing lines	Patch %	Lines
...c/components/MultiSelect/FilterableMultiSelect.tsx	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #20404      +/-   ##
==========================================
+ Coverage   91.39%   91.80%   +0.41%     
==========================================
  Files         485      479       -6     
  Lines       31370    32155     +785     
  Branches     5430     5506      +76     
==========================================
+ Hits        28670    29520     +850     
+ Misses       2547     2488      -59     
+ Partials      153      147       -6     

Flag	Coverage Δ
main-packages	85.04% <77.77%> (+0.10%)	⬆️
web-components	97.31% <ø> (+0.15%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[netlify]

✅ Deploy Preview for carbon-elements ready!

Name	Link
🔨 Latest commit	99f75dd
🔍 Latest deploy log	https://app.netlify.com/projects/carbon-elements/deploys/68b75d7c6fac01000886faa5
😎 Deploy Preview	https://deploy-preview-20404--carbon-elements.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[netlify]

✅ Deploy Preview for v11-carbon-react ready!

Built without sensitive environment variables

Name	Link
🔨 Latest commit	99f75dd
🔍 Latest deploy log	https://app.netlify.com/projects/v11-carbon-react/deploys/68b75d7c57d72300083d2454
😎 Deploy Preview	https://deploy-preview-20404--v11-carbon-react.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[Gururajj77]

Looks good

[netlify]

✅ Deploy Preview for v11-carbon-web-components ready!

Name	Link
🔨 Latest commit	99f75dd
🔍 Latest deploy log	https://app.netlify.com/projects/v11-carbon-web-components/deploys/68b75d7cd2f27d00072185de
😎 Deploy Preview	https://deploy-preview-20404--v11-carbon-web-components.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.