Fix HBase Docker build failures due to outdated buster repositories

[li-boxuan]

Description

This PR fixes HBase test failures caused by Docker build issues where the apt-get update command was failing with exit code 100.

Problem

The HBase tests were failing with the following error:

org.testcontainers.containers.ContainerFetchException: Can't get Docker image
...
Caused by: com.github.dockerjava.api.exception.DockerClientException: Could not build image: The command '/bin/sh -c apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y socat' returned a non-zero code: 100

Root Cause

The issue was caused by using outdated base images:

• openjdk:8-jre-buster in the HBase Dockerfile
• debian:buster-slim in the dist Dockerfile

Debian Buster reached end-of-life and its repositories are no longer accessible via standard URLs, causing apt-get update to fail.

Solution

• Updated HBase Dockerfile base image from openjdk:8-jre-buster to openjdk:8-jre-bullseye
• Updated dist Dockerfile builder stage from debian:buster-slim to debian:bullseye-slim
• Updated default HBase version from 2.5.0 to 2.6.0 to match the version used in HBaseContainer.java

These changes maintain JDK8 compatibility while using more recent and supported Debian repositories.

Testing

• Project compiles successfully with the changes
• No other references to buster remain in the codebase
• HBase download URLs are verified to be accessible

For all changes:

• Is there an issue associated with this PR? Is it referenced in the commit message?
• Does your PR body contain #xyz where xyz is the issue number you are trying to resolve?
• Has your PR been rebased against the latest commit within the target branch (typically master)?
• Is your initial contribution a single, squashed commit?

For code changes:

• Have you written and/or updated unit tests to verify your changes?
• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?
• If applicable, have you updated the LICENSE.txt file, including the main LICENSE.txt file in the root of this repository?
• If applicable, have you updated the NOTICE.txt file, including the main NOTICE.txt file found in the root of this repository?

Notes

• No new dependencies were added
• No license changes required
• This is a infrastructure fix that should resolve the HBase test execution environment

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: openhands-agent / name: OpenHands (3f99047)

[li-boxuan]

not sure why EasyCLA is failing, maybe because the commit has two authors?

[jarias-lfx]

/easycla