Add "detect-label" to canary-release (with the option to override it via input)

[kenodegard]

Checklist

• I added a descriptive title
• I searched open requests and couldn't find a duplicate

What is the idea?

Add the detect label steps from conda & conda-build:

https://github.com/conda/conda/blob/cf3a0fa9ce01ada7a4a0c934e17be44b94d4eb91/.github/workflows/tests.yml#L682-L701

Why is this needed?

The detect label steps have become complex enough (and reused enough) that we might as well add them to this action to avoid tedious and error prone copy paste whenever the workflow needs adjustment.

What should happen?

No response

Additional Context

No response

[kenodegard]

Projects "using" the canary-release workflow: https://github.com/search?q=%2Fuses%3A+conda%5C%2Factions%5C%2Fcanary-release%2F+language%3AYAML+NOT+is%3Afork&type=code