chore: bump Java and Gradle version in Android sample

[yq-yang-qin]

Description

• Bump Java and Gradle version in Android sample

General Checklist

• Added new tests to cover change, if needed
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• If breaking change, documentation/changelog update with migration instructions

By submitting this pull request, I confirm that my contribution is made under the terms of the MIT-0 license.

[zhu-xiaowei]

For build-android actions, Please fix the build error:

error: invalid source release: 21

For the build-ios actions, Please update the runs-on parameter in
https://github.com/aws-samples/swift-chat/actions/runs/12339018149/workflow#L11,
https://github.com/aws-samples/clickstream-sdk-samples/blob/main/.github/workflows/build-rn.yml#L37
to macos-latest and try again.