fix: nix build, downgrade toolchain to go1.23.1

[trevorwhitney]

What this PR does / why we need it:

#14358 bumped the go.mod version to go 1.22, and at the same time bumped the go toolchain to 1.23.2, was there a reason for this discrepency? It broke the nix build, as 1.23.2 isn't available in nixpkgs (or many other package managers) yet. Since the version is still a 1.22, are there any objections to downgrading the patch of the toolchain by one until it's available?

This also changes the nix CI build to run on changes to go.mod to prevent this problem in the future.

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[trevorwhitney]

For context on the faillint fork: fatih/faillint#44

PR was merged, so switched to latest version of fatih/faillint

[cstyan]

we should try to get onto 1.23.2 as soon as nix updates, there's probably not a big downside but ideally we stay consistent on versioning across projects