Remove modcheck from build dependencies to allow local development

The modcheck target was blocking local development by requiring all
go.mod and go.sum changes to be committed before building. This change:

- Removes modcheck from build target dependencies (binary, binary-minimal,
  binary-debug, cli, bench, exporter-minimal)
- Keeps modcheck as a standalone target for CI validation
- Adds explicit modcheck step to golangci-lint workflow for CI validation
- Allows developers to build locally without committing dependency changes
- CI still validates that go.mod and go.sum are properly maintained

This resolves the issue where developers couldn't build after making code
changes that required dependency updates until they committed the go.mod
and go.sum changes first.

Co-authored-by: rchincha <45800463+rchincha@users.noreply.github.com>

.github/workflows/golangci-lint.yaml

@@ -44,6 +44,9 @@ jobs:
           # skip-build-cache: true
         env:
           GOEXPERIMENT: jsonv2
+      - name: Check go.mod and go.sum are up to date
+        run: |
+          make modcheck
       - name: Run linter from make target
         run: |
           make check