Textures: Fix dimensions of video frames.

[Mugen87]

Related issue: #31416 (comment)

Description

The dimension of video frames must be computed specifically.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	338.28 78.93	338.28 78.93	+0 B +0 B
WebGPU	557.43 154.27	557.52 154.28	+90 B +18 B
WebGPU Nodes	556.35 154.05	556.44 154.07	+90 B +19 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	469.62 113.66	469.69 113.69	+66 B +31 B
WebGPU	633.19 171.36	633.35 171.4	+156 B +41 B
WebGPU Nodes	588.33 160.68	588.48 160.72	+156 B +41 B