Fix blank button not resetting project template value

The button didn't override a value, so the old value was posted again.

app/views/projects/_project_templates.html.haml

 .project-templates-buttons.import-buttons{ data: { toggle: "buttons" } }
   .btn.blank-option.active
-    %input{ type: "radio",  autocomplete: "off", name: "project_templates", id: "blank", checked: "true" }
+    %input{ type: "radio",  autocomplete: "off", name: "project[template_name]", id: "blank", checked: "true", value: "" }
     = icon('file-o', class: 'btn-template-icon')
     Blank
   - Gitlab::ProjectTemplate.all.each do |template|

changelogs/unreleased/zj-fix-fe-blank-button.yml

+---
+title: Fix new project form not resetting the template value
+merge_request:
+author:
+type: fixed