Add duplicate check to issue template

Introduced a mandatory duplicate check checkbox in the issue template to prevent duplicate issues. This ensures that contributors verify no existing issue covers the same topic before submission. This change aims to streamline the issue tracking process and improve workflow efficiency.

.github/ISSUE_TEMPLATE/application.yml

@@ -5,6 +5,15 @@ projects:
   - "Computing-For-All/nextjs-issue-tracker"
 
 body:
+  - type: checkboxes
+    id: duplicate_check
+    attributes:
+      label: "Duplicate Check"
+      description: "Please Ensure there isn't an issue already created."
+      options:
+        - label: "I have searched for and didn't find any pre existing issue tracking this"
+          required: true
+
   - type: dropdown
     id: issue_type
     attributes: