Workaround Firefox Leak

[sebavan]

https://forum.babylonjs.com/t/videotexture-memory-leak-in-firefox/34876

[azure-pipelines]

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To prevent this PR from going to the changelog marked it with the "skip changelog" label.

[azure-pipelines]

Snapshot stored with reference name:
refs/pull/13127/merge

Test environment:
https://babylonsnapshots.z22.web.core.windows.net/refs/pull/13127/merge/index.html

To test a playground add it to the URL, for example:

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/13127/merge/index.html#WGZLGJ#4600

Links to test babylon tools with this snapshot:

https://playground.babylonjs.com/?snapshot=refs/pull/13127/merge
https://sandbox.babylonjs.com/?snapshot=refs/pull/13127/merge
https://gui.babylonjs.com/?snapshot=refs/pull/13127/merge
https://nme.babylonjs.com/?snapshot=refs/pull/13127/merge

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