Remove '_No response_' tag

[frankharkins]

Summary

If no tags are selected in the issue template, the labels field is ['_No response_']. This PR replaces this edge case with an empty list.

Fixes #319.

[mickahell]

I think you can also add the mandatory of the field in the issue :)

just need adding to the file : https://github.com/qiskit-community/ecosystem/blob/main/.github/ISSUE_TEMPLATE/submission.yml?plain=1 :

    validations:
      required: true

[frankharkins]

Do you think we should require tags? I'll ask the team what they think too

[mickahell]

From my point of view, it always gonna have a tag for any project. So it could be easy to put it mandatory.

Wait for your team feedback what does they thing about it :)

Every else looks good to me 🚀

[frankharkins]

For now, we won't make tags mandatory, but we will encourage selecting tags and work with submitters to add new tags if they feel that none fit their project.

(Basically, we want all projects to have tags, but we won't force it at the issue stage.)