fix: onboarding/index.html.erb unclosed HTML tags (#10838)

# Pull Request Template

## Description

This was not really an issue because HTML is permissive and auto-closes
these when the parent is closed, but it’s cleaner to do it.
It was also showing errors if you open the project in an IDE.

## Type of change

- Chore

## How Has This Been Tested?

## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] Any dependent changes have been merged and published in downstream
modules

Co-authored-by: Shivam Mishra <scm.mymail@gmail.com>

app/views/installation/onboarding/index.html.erb

@@ -70,7 +70,9 @@
                 Finish Setup
               </button>
             </div>
-          <% end %>
+            <% end %>
+          </div>
+        </section>
       </main>
     </div>
   </body>