fix(noUselessEscapeInRegex): don't report unescaped range sep at the end of a class

[Conaclos]

Summary

Fix a false positive of noUselessEscapeInRegex.

Test Plan

I added a test.

[codspeed-hq]

CodSpeed Performance Report

Merging #3687 will degrade performances by 6.58%

_{Comparing conaclos/noUselessEscapeInRegex-false-positive (1fba723) with main (11956d0)}

Summary

⚡ 1 improvements
❌ 1 regressions
✅ 99 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	conaclos/noUselessEscapeInRegex-false-positive	Change
⚡	dojo_11880045762646467684.js[cached]	8.4 ms	7.9 ms	+6.41%
❌	react.production.min_3378072959512366797.js[cached]	1.9 ms	2 ms	-6.58%