image not found when creating PDF view of objects

[mdetrano]

Describe the bug

When the PDF option is selected from the dropdown arrow when viewing a list of objects, the resulting pdf file created has an X'd-out area with the phrase 'image not found'

To Reproduce

Provide a link to a live example, or an unambiguous set of steps to reproduce this issue. Include configuration, logs, etc. to reproduce, if relevant.

1. Select Overview / Hosts
2. Click the drop down arrow in the header tabs, select PDF
3. The PDF file will open with the described graphical glitch.

Expected behavior

The image glitch should not be present

Screenshots

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Your Environment

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• Icinga Web 2 version and modules (System - About): 2.9.5
• Web browser used: all of them
• Icinga 2 version used (icinga2 --version):
• PHP version used (php --version): 7.2.24
• Server operating system and version: CentOS Stream 8

Additional context

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