asyncapi asyncApi2SchemaValidation does not allow string examples for other schema types

[timonback]

Describe the bug
The spectral rule asyncApi2SchemaValidation currently enforces that all examples have the same type as the schema type. However, we believe that there are cases in AsyncAPI, where it is needed to accept string examples regardless of the schema type.

To Reproduce

1. Use the AsyncAPI document: Allow plain string in Message Example Object field payload for non-json payloads (like xml, yaml) asyncapi/spec#1038 (comment)
2. Open it in AsyncAPI studio (Or run the cli)
   1. Run spectral lint --ruleset rule.yaml test.yaml
   2. With rule.yaml: extends: "spectral:asyncapi"
   3. We had to change the version to 2.6.0, as the cli does not support 3.0.0 yet
3. See the error: 66:11 error asyncapi-schema-examples "0" property type must be object components.schemas.io.github.springwolf.examples.kafka.dtos.XmlPayloadDto.examples[0]

Expected behavior
No error/validation message

Screenshots
N/A

Environment (remove any that are not applicable):

• Library version: develop

Additional context
We are embedding xml and/or yaml as string in examples in an AsyncAPI (JSON) document.

Relates to asyncapi/spec#1038

[timonback]

Update: Identical PR in parser-js has been merged: asyncapi/parser-js#1007

EDIT: actually, it was only updated, not merged yet