feat: Resize textarea using alt+up and alt+down arrow keys

[arbirali]

📝 Description

This PR introduces a keyboard accessibility enhancement to the textarea component, allowing users to resize it vertically using the keyboard. Specifically:

• Pressing Alt + ↑ (Up Arrow) decreases the height of the textarea.
• Pressing Alt + ↓ (Down Arrow) increases the height of the textarea.

This improvement supports keyboard-only users and enhances overall usability.

Related issue: tutor-indigo/#146
Taiga Task (if accessible): US 75 – Keyboard accessible textarea resizing
Live Preview: Profile Page – Sandbox

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🧪 How Has This Been Tested?

• Manually tested across Chrome, Firefox, and Safari.
• Verified that the height increases/decreases correctly with the specified key combinations.
• Confirmed that default textarea behavior and form submission remain intact.

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🖼️ Screenshots/Sandbox (optional):

Before	After
Textarea not resizable via keyboard	Textarea resizable using Alt + ↑ / ↓

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✅ Merge Checklist

• If your update includes visual changes, have they been reviewed by a designer? Send them a link to the Sandbox, if applicable.
• Is there adequate test coverage for your changes?

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📦 Post-merge Checklist

• Deploy the changes to prod after verifying on stage or ask @openedx/2u-infinity to do it.
• 🎉 🙌 Celebrate! Thanks for your contribution.

[codecov]

Codecov Report

Attention: Patch coverage is 14.28571% with 12 lines in your changes missing coverage. Please review.

Project coverage is 65.97%. Comparing base (3601cb6) to head (9cd0b4f).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/profile/forms/Bio.jsx	14.28%	12 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1208      +/-   ##
==========================================
- Coverage   66.82%   65.97%   -0.85%     
==========================================
  Files          51       51              
  Lines         856      870      +14     
  Branches      177      183       +6     
==========================================
+ Hits          572      574       +2     
- Misses        273      285      +12     
  Partials       11       11              

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[awais-ansari]

Please add a test case for this change.