[Bug]: records fields are set to null when there should be a default value assigned

[sahanHe]

Description

When a record is created using a predefined type where several nullable fields with default values, these fields are set to null instead of having the default value. This happens in the repository, client.config

Steps to Reproduce

When debugging the following code, the values of the returned client is set to null instead of having default parameters(defaultTokenExpTime, clockSkew, credentialBearer).

import ballerinax/'client.config;
import ballerina/http;



configurable string refreshToken = "";
configurable string clientId = "";
configurable string clientSecret = "";
configurable string spreadsheetId = "";

ConnectionConfig spreadsheetConfig = {
    auth: {
        clientId: clientId,
        clientSecret: clientSecret,
        refreshToken: refreshToken,
        refreshUrl:"https://www.googleapis.com/oauth2/v3/token"
    }
};

public type ConnectionConfig record {|
    *config:ConnectionConfig;
    # Configurations related to client authentication
    http:BearerTokenConfig|config:OAuth2RefreshTokenGrantConfig auth;
    # The HTTP version understood by the client
    http:HttpVersion httpVersion = http:HTTP_1_1;
|};

public function main() returns error? {
    http:ClientConfiguration|error httpClientConfig = config:constructHTTPClientConfig(spreadsheetConfig);
}

Affected Version(s)

2201.9.0

OS, DB, other environment details and versions

No response

Related area

-> Runtime

Related issue(s) (optional)

https://github.com/ballerina-platform/ballerina-library/issues/6023

Suggested label(s) (optional)

No response

Suggested assignee(s) (optional)

No response