WebGPURenderer: Fix change the current canvas samples

[sunag]

Related issue: #31743 (comment)

Description

Fix change the current canvas samples.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	338.24 79.14	338.24 79.14	+0 B +0 B
WebGPU	586.56 161.9	586.6 161.94	+43 B +32 B
WebGPU Nodes	585.17 161.66	585.21 161.69	+43 B +33 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	469.7 113.74	469.7 113.74	+0 B +0 B
WebGPU	656.01 177.4	656.05 177.43	+43 B +25 B
WebGPU Nodes	610.01 166.57	610.05 166.6	+43 B +25 B