grafana-agent: build with [email protected]

[stefanb]

Workaround for

• Conflicting router patterns when built with Go 1.23 grafana/agent#6972

Use "go" again when grafana/agent#6972 is resolved and released

Follow-up to

• go 1.23, [email protected] 1.22.6 (new formula) #175310

---

• Have you followed the guidelines for contributing?
• Have you ensured that your commits follow the commit style guide?
• Have you checked that there aren't other open pull requests for the same formula update/change?
• Have you built your formula locally with HOMEBREW_NO_INSTALL_FROM_API=1 brew install --build-from-source <formula>, where <formula> is the name of the formula you're submitting?
• Is your test running fine brew test <formula>, where <formula> is the name of the formula you're submitting?
• Does your build pass brew audit --strict <formula> (after doing HOMEBREW_NO_INSTALL_FROM_API=1 brew install --build-from-source <formula>)? If this is a new formula, does it pass brew audit --new <formula>?

---