build(deps): remove 'case' dependency

[Conaclos]

Summary

Use biome_string_case instead of case.

Test Plan

CI should pass.

[github-actions]

Parser conformance results on

js/262

Test result	main count	This PR count	Difference
Total	49701	49701	0
Passed	48721	48721	0
Failed	980	980	0
Panics	0	0	0
Coverage	98.03%	98.03%	0.00%

jsx/babel

Test result	main count	This PR count	Difference
Total	40	40	0
Passed	37	37	0
Failed	3	3	0
Panics	0	0	0
Coverage	92.50%	92.50%	0.00%

symbols/microsoft

Test result	main count	This PR count	Difference
Total	6322	6322	0
Passed	2036	2036	0
Failed	4286	4286	0
Panics	0	0	0
Coverage	32.20%	32.20%	0.00%

ts/babel

Test result	main count	This PR count	Difference
Total	662	662	0
Passed	593	593	0
Failed	69	69	0
Panics	0	0	0
Coverage	89.58%	89.58%	0.00%

ts/microsoft

Test result	main count	This PR count	Difference
Total	17646	17646	0
Passed	13439	13439	0
Failed	4205	4205	0
Panics	2	2	0
Coverage	76.16%	76.16%	0.00%

[codspeed-hq]

CodSpeed Performance Report

Merging #2561 will improve performances by 6.12%

_{Comparing conaclos/remove-case-dep (5a17f88) with main (f42263d)}

Summary

⚡ 1 improvements
✅ 92 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	conaclos/remove-case-dep	Change
⚡	eucjp.json[uncached]	5.2 ms	4.9 ms	+6.12%