Setting the default layer mask onto layer 1 otherwise everything is disabled by default

[fcoulombe]

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Purpose of this PR

Why is this PR needed, what hard problem is it solving/fixing?

This makes it consistent with what happens in URP and HDRP

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Testing status

Describe what manual/automated tests were performed for this PR

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Comments to reviewers

Notes for the reviewers you have assigned.

[sebastienlagarde]

hi, please add a changelog and also comment what you tested. Thank you

[fcoulombe]

we apparently don't want to modify the behavior to align with future pipeline.