PR: Remove installers workflow step validation for spyder conda package build to be done only on PRs (CI)

[dalthviz]

Description of Changes

As part of the Spyder 6alpha2 release I did the release candidate step and tried to generate the installers, but seems like the manual worflow dispatch fails due to the spyder conda package build step being skipped (seems like it was skipped if the workflow is not being run from a PR). Not totally sure if this is the correct approach but opening a PR just in case and to discuss if something else needs to be done @ccordoba12 @mrclary

• Workflow run that failed: https://github.com/spyder-ide/spyder/actions/runs/6053595167

Affirmation

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and understand I am releasing the same under Spyder's MIT (Expat) license.

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[ccordoba12]

I'll let @mrclary review this one because I'm not sure if this is the right approach.

[mrclary]

Okay, I'll look at it this weekend. I'm away from my computer right now.

[mrclary]

@dalthviz, thank you for catching this. Yes, your proposed changes are correct. This was an error on my part when refactoring the workflows for caching. The spyder conda package should be built for all workflow conditions.