fix: wysiwyg textarea width when window zoom !== 100%

[zsviczian]

fixes: #7847

Here's my test container: https://excalidraw-6pc2v020f-excalidraw.vercel.app/#json=aZ4Unb4qtOAVvp-rvjsY-,sj2COn1LEP7E9F0ozvf49Q

If you copy/paste this into excalidraw.com production and change browser zoom to 110% the text jumps on edit.

[vercel]

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[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔴	Lines	64.35% (🎯 70%)	47460 / 73744
🔴	Statements	64.35% (🎯 70%)	47460 / 73744
🔴	Functions	65.26% (🎯 68%)	1411 / 2162
🟢	Branches	79.89% (🎯 70%)	5684 / 7114

File Coverage

File	Stmts	% Branch	% Funcs	% Lines	Uncovered Lines
Changed Files
packages/excalidraw/element/textWysiwyg.tsx	84.71%	79.34%	81.25%	84.71%	63-64, 66-67, 120-121, 308-338, 363-369, 371-373, 377, 484-486, 500-501, 513-518, 549-550, 558-559, 582, 588-616, 633, 635, 638-643, 670-673

Generated in workflow #2197