Revert "chore: remove google-cloud-network-connectivity from state.yaml" (#16118)

Given that the changes in cl/882798624 to fix the namespace for this
library are in, we can onboard this to librarian again.

Author: ohmayr

.librarian/state.yaml

@@ -2442,6 +2442,24 @@ libraries:
     remove_regex:
       - packages/google-cloud-netapp/
     tag_format: '{id}-v{version}'
+  - id: google-cloud-network-connectivity
+    version: 2.13.0
+    last_generated_commit: d252e591a655910c3d1b581aadfb11e68c8ff294
+    apis:
+      - path: google/cloud/networkconnectivity/v1
+        service_config: networkconnectivity_v1.yaml
+      - path: google/cloud/networkconnectivity/v1alpha1
+        service_config: networkconnectivity_v1alpha1.yaml
+      - path: google/cloud/networkconnectivity/v1beta
+        service_config: networkconnectivity_v1beta.yaml
+    source_roots:
+      - packages/google-cloud-network-connectivity
+    preserve_regex:
+      - packages/google-cloud-network-connectivity/CHANGELOG.md
+      - docs/CHANGELOG.md
+    remove_regex:
+      - packages/google-cloud-network-connectivity/
+    tag_format: '{id}-v{version}'
   - id: google-cloud-network-management
     version: 1.33.0
     last_generated_commit: 6df3ecf4fd43b64826de6a477d1a535ec18b0d7c