Update GraalVM learn page with Java 21

### Description

> $Subject

Need to update the Java version. Regenerate console outputs and docker files and update

- [x] Update [GraalVM local build learn page](https://ballerina.io/learn/build-the-executable-locally/)
- [x] Update [GraalVM cloud build learn page](https://ballerina.io/learn/build-the-executable-in-a-container/)

### Version

Ballerina SwanLake Update 11