Describe the bug
On meeting's listing page, results per page selector will reset the chosen value if new filters are applied.

To Reproduce
Steps to reproduce the behavior:

1. Go to meeting's index page (bot process and directory)
2. Click on "Results per page" and choose a new value (Ex. 50)
3. From filters side try to apply a new selection
4. "Results per page" value will be changed and will display the initial value (20)

Expected behavior
"Results per page" should take into account the chosen value even if new filters are applied.

Screenshots

(Results per page after choosing a new value - 50)

(Results per page after applying new filters)

Stacktrace
If applicable, add the error stacktrace to help explain your problem.

Extra data (please complete the following information):

• Device: [e.g. iPhone6, Desktop]
• Device OS: [e.g. iOS8.1, Windows 10]
• Browser: [e.g. Chrome, Firefox, Safari]
• Decidim Version: [e.g. 0.10]
• Decidim installation: [e.g. MetaDecidim]

Additional context
Add any other context about the problem here. For instance, add Metadecidim link.