Refactor Alloy Prod Upstreams Workflow

[shammowla]

1. Kept the edgeBasePath input in the workflow_dispatch event for manual triggering.
2. Removed EDGE_BASE_PATH from the global env section to avoid conflicts.
3. Updated the saucelabs/saucectl-run-action step to use the input edgeBasePath.
4. Aligned the structure with the main prod workflow for consistency.
5. Added error handling and Slack notifications for test failures.

Description

Related Issue

Motivation and Context

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (non-breaking change which does not add functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA or I'm an Adobe employee.
• I have made any necessary test changes and all tests pass.
• I have run the Sandbox successfully.

[jonsnyder]

did you mean to add a "-" here before "ee"?

[carterworks]

1. Address Jon's comment about the extra "-"
2. The PR description mentions "Added error
   handling and Slack notifications for test failures", but I don't see anything that reflects that in the code. Where is it?

I know the Slack notifications in #alloy-ci, as it is right now, are supposed to show a bunch of info, but none of that comes through—notice how all the info at the beginning of the message is blank.