docs: Update INSTALL.md for frontend build instructions

[he1l0world]

Description

This PR updates the INSTALL.md file to ensure smoother frontend setup.

Relevant change with #8923, which updated the Node.js runtime to 16.x.

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• build/CI
• test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

N/A

How Has This Been Tested?

• Followed updated instructions on a fresh setup using Node.js 16.x and verified successful npm run build and frontend access using CS_URL=http://localhost:8080.

• Relevant change with #8923, which updated the Node.js runtime to 16.x.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 16.57%. Comparing base (4662ffc) to head (75ccfa3).
Report is 2 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #11057      +/-   ##
============================================
- Coverage     16.60%   16.57%   -0.03%     
- Complexity    13927    13968      +41     
============================================
  Files          5730     5743      +13     
  Lines        508254   510468    +2214     
  Branches      61789    62073     +284     
============================================
+ Hits          84395    84617     +222     
- Misses       414420   416389    +1969     
- Partials       9439     9462      +23     

Flag	Coverage Δ
uitests	3.90% <ø> (-0.04%)	⬇️
unittests	17.47% <ø> (-0.03%)	⬇️

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