fix: Converts snapshot_id field from required to optional.

[marcosuma]

Description

Please include a summary of the fix/feature/change, including any relevant motivation and context.

Link to any related issue(s): CLOUDP-228582

Type of change:

• Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR.
• Breaking change (fix or feature that would cause existing functionality to not work as expected). Please, add the "breaking change" label to the PR.
• This change requires a documentation update
• Documentation fix/enhancement

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Further comments

[github-actions]

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[maastha]

LGTM