Override option for architecture when running the jar

[samfreund]

Description

This lets us perform better smoketests.

Meta

Merge checklist:

• Pull Request title is short, imperative summary of proposed changes
• The description documents the what and why
• If this PR changes behavior or adds a feature, user documentation is updated
• If this PR touches photon-serde, all messages have been regenerated and hashes have not changed unexpectedly
• If this PR touches configuration, this is backwards compatible with settings back to v2025.3.2
• If this PR touches pipeline settings or anything related to data exchange, the frontend typing is updated
• If this PR addresses a bug, a regression test for it is added

[Gold856]

It's would be more accurate to call the arg "platform" because architecture implies CPU architecture.

[crschardt]

Should this PR include a test for the new platform option?

[samfreund]

Should this PR include a test for the new platform option?

I'm not sure how precisely we could test it, since we can't actually run the jar from inside the jar itself. It will be tested in #2248 somewhat indirectly, and we've already confirmed the override works with Playwright; so I think it should be fine.

[samfreund]

Combining with #2248