fix: noVar ignores TsGlobalDeclaration

[vasucp1207]

Summary

Closes #1651

Test Plan

New test case added,

declare global {
    var Txt: CustomWindow['Txt'];
}

[netlify]

✅ Deploy Preview for biomejs canceled.

Name	Link
🔨 Latest commit	26373bc
🔍 Latest deploy log	https://app.netlify.com/sites/biomejs/deploys/65b29ef469663100085f5861

[codspeed-hq]

CodSpeed Performance Report

Merging #1669 will improve performances by 13.55%

_{Comparing vasucp1207:noVarTsGlobal (26373bc) with main (c0ee00b)}

Summary

⚡ 8 improvements
✅ 85 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	vasucp1207:noVarTsGlobal	Change
⚡	analyzer[router.ts]	85.9 ms	75.7 ms	+13.55%
⚡	analyzer[index.js]	201.8 ms	181.9 ms	+10.94%
⚡	analyzer[parser.ts]	297.4 ms	263.5 ms	+12.84%
⚡	analyzer[css.js]	84.4 ms	77.1 ms	+9.52%
⚡	analyzer[statement.ts]	266.6 ms	235.6 ms	+13.18%
⚡	analyzer[lint.ts]	156.7 ms	140.8 ms	+11.31%
⚡	analyzer[typescript.ts]	425.2 ms	379.4 ms	+12.05%
⚡	db.json[cached]	77.5 ms	71.4 ms	+8.45%

[Conaclos]

@vasucp1207 feel free to merge once approved