[Information Panel] Allows to refresh icon and metadata for urls such as trash:/

Summary: CCBUG: 392882

Test Plan:
1. Create a file
2. Remove it, so that it goes to the trash
3. Open trash
4. Empty trash

Before:
Information panel icon is still user-trash-full

After:
Information panel icon is changed to user-trash

Reviewers: ngraham, #dolphin, elvisangelaccio

Reviewed By: ngraham, #dolphin, elvisangelaccio

Subscribers: kfm-devel

Tags: #dolphin

Differential Revision: https://phabricator.kde.org/D23668