feat: ENT-3844 remove extraneous dependencies added during prior work

[binodpant]

Why?

I noted that these two fortawesome libs are used directly by frontend learner portal and are makred as peer deps here but not used within this project. And they are already depended on by FE learner portal. hence they can be safely removed.

These were added in this commit: https://github.com/edx/frontend-enterprise/blob/a461a769faa2766aebe99f6d9de6fb110a54876b/package.json

"@fortawesome/fontawesome-svg-core": "^1.2.17",
"@fortawesome/free-brands-svg-icons": "^5.11.2",
"@fortawesome/free-regular-svg-icons": "^5.12.1",

but the only one actually used here is fortawesome/free-solid-svg-icons

I tested locally by using the new package of frontend-enterprise installed into frontend learner portal