[BUG] v7.3 mdi icons not working by v6 OK

[ctny]

Deployment details:

• App version [e.g. v1.7.4]: v2.3.1
• Platform [e.g. amd64, arm64, arm/v7]: uraid docker image by pawelmalak
• Docker image tag [e.g. latest, multiarch]: latest

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Bug description:

A clear and concise description of what the bug is.

v7.3 icons from https://pictogrammers.com/library/mdi/ do not show up corrected in Flames. v6 icons are fine.

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Steps to reproduce:

1. add a new menu item
2. click on "click here for reference" to find an icon
3. add any v7.3 icons, example, generator-portable or power-plug-battery, icon will not show up
4. add any v6 icons, example, home-battery, icon will show up in flame menu correctly