Pagination issue related to filters searching

[mnemonicGraf]

Issue Summary
List of the alerts after spcify filtering criteria isn't listed on one page.
Alerts are visible on few pages even there is place on first page.

Environment

OS: Linux
API version: 9.0.1
Deployment: Docker
Database: Postgres
web UI version: 8.7.0

Prerequisite
It is easier to see this when there are more alerts than 100

Steps to reproduce:

1. Open "Filters" menu.
2. Write string for search in the field.
3. Close filter.
4. Check the alerts list.

Expected
Number of alerts is changed. All alerts are visible on first page (if "Rows per page" allow for this).

Result
Number of alerts is not changed. Alerts can be found on few pages even there still is place for them on the first page.