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_test.go

@@ -640,6 +640,7 @@ body:
       description: Description of input
       placeholder: Placeholder of input
       value: Value of input
+      hide_label: true
     validations:
       required: true
       is_number: true
@@ -681,8 +682,6 @@ body:
 
 ` + "```bash\nValue of id2\n```" + `
 
-### Label of input
-
 Value of id3
 
 ### Label of dropdown