ci: disable automatic AI triage workflows (#5569)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/workflows/models_issue_triage.yml

@@ -1,8 +1,7 @@
 name: Issue Triage (Models)
 
 on:
-  issues:
-    types: [opened]
+  workflow_dispatch:
 
 permissions:
   issues: write

.github/workflows/models_pr_triage.yml

@@ -1,8 +1,7 @@
 name: PR Triage (Models)
 
 on:
-  pull_request_target:
-    types: [opened, edited]
+  workflow_dispatch:
 
 permissions:
   pull-requests: write

.github/workflows/moderate.yml

@@ -1,11 +1,6 @@
 name: AI Moderator
 on:
-  issues:
-    types: [opened]
-  issue_comment:
-    types: [created]
-  pull_request_review_comment:
-    types: [created]
+  workflow_dispatch:
 
 jobs:
   spam-detection: