Result per page selection form on dashboard edit conflicts with other form on page

[Ghada El-Zoghbi]

Mahara: 19.04.0
OS: Linux 16.04
DB: Postgres
Browser: FF and Chrome

When a block - such as My Portfolios - is on the dashboard, the 'Results per page' section does not work.

This is due to the fact that the selection item is wrapped in a form. But, there is already a higher level form in play for adding blocks on the page.

To reproduce:
1. Create at least 11 pages for a user.
2. For the same user, edit the user dashboard
3. Make sure the 'My Portfolios' block is on the dashboard.
4. While in Edit mode, select '20' for the 'Results per page'

Current Action:
Nothing happens (only the original 10 pages continue to display)

Expected Result:
The list of portfolios for the block should display the 11 user pages.

This will also be the case for the Watched pages block.

The issue is because of this template:

* htdocs/theme/raw/templates/view/blocks.tpl

Which wraps the first form around the pagination form (which is created in lib/web.php:: build_pagination())

If the outer form is closed before the other form, the theme breaks.