Allow issue templates to not render title (#22589)

This adds a yaml attribute that will allow the option for when markdown
is rendered that the title will be not included in the output

Based on work from @brechtvl

modules/issue/template/template.go

@@ -259,7 +259,9 @@ func (f *valuedField) WriteTo(builder *strings.Builder) {
 	}
 
 	// write label
-	_, _ = fmt.Fprintf(builder, "### %s\n\n", f.Label())
+	if !f.HideLabel() {
+		_, _ = fmt.Fprintf(builder, "### %s\n\n", f.Label())
+	}
 
 	blankPlaceholder := "_No response_\n"
 
@@ -311,6 +313,13 @@ func (f *valuedField) Label() string {
 	return ""
 }
 
+func (f *valuedField) HideLabel() bool {
+	if label, ok := f.Attributes["hide_label"].(bool); ok {
+		return label
+	}
+	return false
+}
+
 func (f *valuedField) Render() string {
 	if render, ok := f.Attributes["render"].(string); ok {
 		return render