Replace React Helment with Gatsby Head

## Summary

There was a warning within the console that recommended we use the built-in Gatsby head component as of Gatsby `v4.19.0`. This should reduce the amount of third-party dependencies we need. For the most part it also seems like it will reduce the amount of direct package size as well.

[Documentation for Gatsby Head](https://gatsby.dev/gatsby-head)

Warning produced from the run command:

```
warn gatsby-plugin-react-helmet: Gatsby now has built-in support for modyfing
the document head. Learn more at https://gatsby.dev/gatsby-head
```