ObjectTypeVisitor - cast to OpenApiSchemaAcceptor instead of IOpenApiSchemaAcceptor

[Wozbo]

Describe the issue
azure-functions-openapi-extension/src/Microsoft.Azure.WebJobs.Extensions.OpenApi.Core/Visitors
/ObjectTypeVisitor.cs

Line ~110 ish, there is a line that reads var instance = acceptor as OpenApiSchemaAcceptor;. When testing with a custom
IOpenApiSchemaAcceptor, this was not processing, its because we cast to the concrete implementation type instead of the interface type. This stumped us recently, debugging attribute errors with duplicate keys.

Expected behavior
I think this should be var instance = acceptor as IOpenApiSchemaAcceptor

Screenshots
If applicable, add screenshots to help explain your issue.

[Wozbo]

Adding to this, seems like this is also an issue in TypeVisitor.cs, line ~126 ish