Updating FontAwesome Icons in Admin area

[N8Solutions]

Some FontAwesome icons do not work properly when J2Store is added to Joomla. This happens whether in J3 or J4. These changes are for compatibility with newer versions of Joomla and FontAwesome 5.

J2Store can be downloaded for free from here: https://github.com/J2Store4/j2store4/releases

Icons that get broken:

• arrows for the spacer particle
• TM (trademark) for the branding particle
• For other particles that utilize the pencil, copy, trash FA icons

For the Branding particle located in: engines\common\nucleus\particles and the files branding.yaml branding.html.twig

In Gantry 5 the branding particle has the class fa fa-fw fa-trademark on the left side menu of particles but fas fa-fw fa-trademark is more compatible. When the branding particle is added to a layout, it again has the class fa fa-trademark, and changing it to fas fa-trademark fixes the problem. However, I'm unable to figure out where to make these changes for this particle so it displays properly.

These changes fix the issue and they are still compatible with a fresh install of Gantry 5. Just need to fix the Branding particle.

[N8Solutions]

@JoomFX I wanted to bring this pull request to your attention as well. Thought you'd like to check out the suggested changes I've made to fix the issue. I'm hoping @hexplor will review and include these changes for the next version of Gantry 5.