[DOC] Onboard expired password identification API documentation

[Thisara-Welmilla]

With the feature [1], the password expired users identification API is on-boarded to the product is. Need to improve the official IS-Serve doc space with the new API specification.
Updated yaml: https://github.com/wso2/identity-api-server/blob/master/components/org.wso2.carbon.identity.api.expired.password.identification/org.wso2.carbon.identity.api.expired.password.identification.v1/src/main/resources/ExpiredPasswordIdentification.yaml

[1]. #16529

[AnuradhaSK]

It's documented https://is.docs.wso2.com/en/latest/apis/password-expiring-users-identification-rest-api/