Update searchbar parameters on URL change

Summary:
Searchbar options (text and options) were only updated when toggling the search on, $
Main use case is when changing between stored search urls in Places panel.

Test Plan:
- Store two search urls in Places panel
- Navigate between them
- The searchbar text and parameters change accordingly

BEFORE:
{F7500811}
AFTER:
{F7500813}

Reviewers: #dolphin, elvisangelaccio

Subscribers: kfm-devel

Tags: #dolphin

Differential Revision: https://phabricator.kde.org/D24369