Investigate local version in production packages

[xrmx]

Describe the bug:

6.21.4 got published to the production pypi (https://pypi.org/project/elastic-apm/#history) with a local release. That was not supposed to happen and local version should only have been added to the test packages.
Packages has been built from this actions run https://github.com/elastic/apm-agent-python/actions/runs/8347027212

To Reproduce

1. push a tag

Environment (please complete the following information)

• OS: [e.g. Linux]
• Python version:
• Framework and version [e.g. Django 2.1]:
• APM Server version:
• Agent version:

Additional context

[xrmx]

@elastic/observablt-ci can you help with this please?

[v1v]

The evil elvis didn't work correctly, since it was triggered with the workflow_call:

• https://github.com/elastic/apm-agent-python/actions/runs/8347027212/job/22845710899#step:3:9

[amannocci]

The '' is coerced to false, and as a result, the other value is always returned.
I will create PR to fix the issue.