CloudWatch: Backport aws-sdk-go-v2 update from external plugin (#107136)

* CloudWatch: Backport aws-sdk-go-v2 update from external plugin

* Review feedback & cleaning up a couple typos

pkg/tsdb/cloudwatch/middleware_test.go

@@ -0,0 +1,39 @@
+package cloudwatch
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/grafana/grafana/pkg/tsdb/cloudwatch/models"
+)
+
+func Test_Middleware(t *testing.T) {
+	t.Run("rejects POST method", func(t *testing.T) {
+		rr := httptest.NewRecorder()
+		req := httptest.NewRequest("POST", "/dimension-keys?region=us-east-1", nil)
+		ds := newTestDatasource()
+		handler := http.HandlerFunc(ds.resourceRequestMiddleware(func(_ context.Context, parameters url.Values) ([]byte, *models.HttpError) {
+			return []byte{}, nil
+		}))
+		handler.ServeHTTP(rr, req)
+		assert.Equal(t, http.StatusMethodNotAllowed, rr.Code)
+	})
+
+	t.Run("should propagate handler error to response", func(t *testing.T) {
+		rr := httptest.NewRecorder()
+		req := httptest.NewRequest("GET", "/some-path", nil)
+		ds := newTestDatasource()
+		handler := http.HandlerFunc(ds.resourceRequestMiddleware(func(_ context.Context, parameters url.Values) ([]byte, *models.HttpError) {
+			return []byte{}, models.NewHttpError("error", http.StatusBadRequest, fmt.Errorf("error from handler"))
+		}))
+		handler.ServeHTTP(rr, req)
+		assert.Equal(t, http.StatusBadRequest, rr.Code)
+		assert.Equal(t, `{"Message":"error: error from handler","Error":"error from handler","StatusCode":400}`, rr.Body.String())
+	})
+}