Complete Enzyme to React Testing Library migration

[kuan121]

High Level Overview of Change

1. Upgrade qs from 6.5.3 to 6.14.1
2. Complete the Enzyme to React Testing Library migration, and remove all code and dependency on Enzyme libraries.

Context of Change

This PR originated from an attempt to upgrade qs from 6.5.3 to 6.14.1 (details) to address a security vulnerability. Although qs is not a direct dependency, it is pulled in transitively through the following chain:jest-enzyme → jest-environment-enzyme → jest-environment-jsdom@24.9.0 → jsdom@11.12.0 → request@2.88.2 → qs@6.5.3

Since we also plan to migrate from Enzyme to React Testing Library, I took this opportunity to complete that migration as part of this PR.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking change that only restructures code)
• Tests (You added tests for code that already exists, or your new feature included in this PR)
• Documentation Updates
• Translation Updates
• Release

Codebase Modernization

• Updated files to React Hooks
• Updated files to TypeScript
• Updated tests to React Testing Library

Before / After

N/A

Test Plan

Coverage Summary Comparison

Metric	Before (CI run)	After (CI run)	Change
Statements	87.8% (7697/8766)	88.04% (7737/8788)	+0.24% ↑
Branches	74.22% (3147/4240)	72.8% (3475/4773)	-1.42% ↓
Functions	81.53% (1245/1527)	82.01% (1254/1529)	+0.48% ↑
Lines	87.64% (7283/8310)	87.88% (7322/8331)	+0.24% ↑
Test Suites	255 passed	255 passed	—
Tests	1256 passed	1256 passed	—
Time	125.96s	106.64s	-19.3s (15% faster) ↑

Key Takeaways

• Statements, Functions, and Lines coverage improved slightly
• Branch coverage dropped 1.42%
• Tests run ~15% faster (19 seconds saved)
• All 1256 tests continue to pass