OpenAPI 3.1.0 support: implement JSON Schema 2020-12 keywords into `sample` plugin

[char0n]

We're missing support for following JSON Schema 2020-12 keywords in SwaggerUI:

• dependentRequired keyword
• not keyword
• if keyword
• then keyword
• else keyword
• dependentSchemas
• prefixItems
• patternProperties
• propertyNames
• unevaluatedItems
• unevaluatedProperties

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The goal of this issue is to analyze the missing keywords and implement them to samples plugin if it make sense to include the keywords into example generation.

Refs #8577