Fix ai_dynint_always_enabled bypassing misc. criteria on dynamic interactions

[Blixibon]

This fixes an issue in Mapbase v7.2 in which the ai_dynint_always_enabled cvar was overriding dynamic interaction misc. criteria (i.e. keyvalues which use Response System criteria). Some comments associated with this code have also been updated.

Note that no default interactions use misc. criteria and some mods (e.g. E:Z2) override this code anyway.

---

PR Checklist

• My PR follows all guidelines in the CONTRIBUTING.md file
• My PR targets a develop branch OR targets another branch with a specific goal in mind

[1upD]

I had to read through these changes a couple of times to understand what's happening here, but I think I understand! The change looks good to me.