adopt golangci-lint v2 (#31222)

* adopt golangci-lint v2

No actual linting changes in this commit, just upgraded tooling and
directives to ignore new linter rules. Adopting v2 solves some
gosec issues in v1 and also happens to be a nice performance boost!
As part of this PR, we also drop support for `MM_NO_ENTERPRISE_LINT`
which hasn't been need for a while anyway.

* simplify: go install is fine!

* missing GOBIN

* golangci-lint: drop legacy preset exclusion

.github/workflows/server-ci-template.yml

@@ -130,7 +130,7 @@ jobs:
       - name: Run plugin-checker
         run: make plugin-checker
       - name: Run mattermost-vet
-        run: make vet BUILD_NUMBER='${GITHUB_HEAD_REF}' MM_NO_ENTERPRISE_LINT=true
+        run: make vet BUILD_NUMBER='${GITHUB_HEAD_REF}'
   check-mattermost-vet-api:
     name: Vet API
     runs-on: ubuntu-22.04