You can read more about the godot license here:
And the 3rd party part licenses of godot here:
To answer your question:
If I understand correctly, this file contains the license for the logo:
Which basically says (a.t.m.) that the LOGO is released under the CC-BY 3.0 license:
This license allows you to use the logo in commercial projects. However, you would have to name (=attribution) the creator of the logo ( Andrea Calabró ) and the license somewhere in the credits section of this project.
So you don't need to change the license of your own project. And you're allowed to sell/hire your project. But there's this attribution obligation which basically means that the user of your software must somehow be able to see who is the author of that logo and under which license.
I am no lawyer so this is no legal advice and all without warranty of being correct. :-)