go.mod: Re-organize dependencies

[timflannagan]

Description

This PR re-organizes the root go.mod. Previously, the first require directive had a mix of direct and indirect dependencies, which is a surprising organization for Go-based projects. Now, those indirect dependencies have been moved to the same require directive with the rest of the indirect dependencies.

Additionally, there were two require directives for the direct dependencies. While this isn't a big issue, there didn't seem to be a reason or theme that explains why these dependencies were separated.

Related to #10496.

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works