fix: update GitHub Actions workflow for Java example

[SimiHunjan]

Updated the GitHub Actions workflow to use Ubuntu as the runner and modified environment variables for the mirror node. Replaced Node.js setup with Homebrew installation and updated the Solo CLI installation method.

Description:

Related issue(s):

Fixes #

Notes for reviewer:

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

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[theekrystallee]

thanks for the PR @SimiHunjan. are we not using the hashgraph runner anymore?

@andrewb1269

[andrewb1269]

@theekrystallee we certainly should be using the hashgraph hosted runners, not the generic Ubuntu latest runner.

[SimiHunjan]

This was test to validate that the standard GitHub runners can run Solo without any issues as before the memory footprint was to high and failed on standard GitHub runners.

Is it really required to use self hosted runners if the standard GitHub runners serves the purpose? I can switch it back, but was planning to leave it here as a case for Solo working on a standard GitHub runner. @andrewb1269

[andrewb1269]

This was test to validate that the standard GitHub runners can run Solo without any issues as before the memory footprint was to high and failed on standard GitHub runners.

Is it really required to use self hosted runners if the standard GitHub runners serves the purpose? I can switch it back, but was planning to leave it here as a case for Solo working on a standard GitHub runner. @andrewb1269

@SimiHunjan - yep, we always push towards self-hosted runners unless there's a specific reason we cannot use them. This is to ensure consistency and security across all repos.