refactor(atomic): optimize validation schema declarations / instantiations

[fbeaudoincoveo]

Task Description

Declare every Bueno prop validation schema used by the ValidatePropsController in Lit-migrated Atomic components as private a static readonly class property.

This has already been done for several components (e.g., atomic-result-timespan), but remains to be done for others (e.g., atomic-sort-expression).

This allows the schema to be initialized only once even if there are multiple instances of the component in the same page.

Acceptance Criteria

•  Every validation schema used by ValidatePropsController in Lit-migrated Atomic components is declared / instantiated as private static readonly class property
• No other validation schemas have been touched
• No other part of the code has been touched
• All tests still pass without any modifications

Technical Notes

No response

Jira Ticket

https://coveord.atlassian.net/browse/KIT-5339