test: add dependabot coverage upload workflow pointing at dependabot-codecov-fix branch

[chsrimanaswi]

Description

Adds the dependabot-coverage-upload.yml caller workflow for testing the Dependabot codecov fix. Points at adobe/aio-reusable-workflows@dependabot-codecov-fix branch. Will be updated to @main once the fix is validated.

Related Issue

https://jira.corp.adobe.com/browse/ACNA-4537

Motivation and Context

Testing ground for [adobe/aio-reusable-workflows#dependabot-codecov-fix] before rolling out to all App Builder repos. Using aio-e2e-tests as a low-risk repo to validate the end-to-end flow.

How Has This Been Tested?

This PR itself is the test, once merged to master, a Dependabot PR on this repo will trigger the artifact-save path in CI, and commenting /upload-coverage as an admin will validate the full upload flow.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.