[chore][receiver/awscontainerinsights] Enable goleak checks (#32404)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
Enable `goleak` checks on the `cadvisor` package of the AWS Container
Insights receiver to help ensure no goroutines are being leaked.

**Link to tracking Issue:** <Issue number if applicable>
#30438

**Testing:** <Describe what testing was performed and which tests were
added.>
This package is a linux-only package, so I wasn't able to test locally,
but CI/CD tests are passing.

Co-authored-by: Sean Marciniak <30928402+MovieStoreGuy@users.noreply.github.com>

receiver/awscontainerinsightreceiver/internal/cadvisor/package_test.go

@@ -0,0 +1,14 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package cadvisor
+
+import (
+	"testing"
+
+	"go.uber.org/goleak"
+)
+
+func TestMain(m *testing.M) {
+	goleak.VerifyTestMain(m)
+}