fix fragdepthblock issue

[deltakosh]

No description provided.

[bjsplat]

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Snapshot stored with reference name:
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WebGL2 visualization test reporter:

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/15204/merge/testResults/webgl2playwright/index.html

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Visualization tests for WebGPU (Experimental)

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/15204/merge/testResults/webgpuplaywright/index.html

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