Add result object namespace to the metrics

[koshkarov]

Closes #

📑 Description

This feature adds a result object namespace to the k8sgpt_number_of_results and k8sgpt_number_of_results_by_type metrics, enabling the creation of more granular dashboards.

Currently, we can only see the total number of results and result types across the cluster. With this change, we will be able to query results by the namespace of the result object.

✅ Checks

• My pull request adheres to the code style of this project
• My code requires changes to the documentation
• I have updated the documentation as required
• All the tests have passed

ℹ Additional Information

Initiaal slack thread: https://k8sgpt.slack.com/archives/C050SKW7SHF/p1745417335572699

Testing

Covered with unit tests
Performed testing running the operator in Local mode with in-cluster K8sGPT service:

# HELP k8sgpt_number_of_results The total number of results
# TYPE k8sgpt_number_of_results gauge
k8sgpt_number_of_results{k8sgpt="k8sgpt-cluster-config",object_namespace="fortio"} 1
k8sgpt_number_of_results{k8sgpt="k8sgpt-cluster-config",object_namespace="istio-system"} 1
k8sgpt_number_of_results{k8sgpt="k8sgpt-cluster-config",object_namespace="k8sgpt-operator-system"} 2
k8sgpt_number_of_results{k8sgpt="k8sgpt-cluster-config",object_namespace="kube-system"} 3
# HELP k8sgpt_number_of_results_by_type The total number of results by type
# TYPE k8sgpt_number_of_results_by_type gauge
k8sgpt_number_of_results_by_type{k8sgpt="k8sgpt-cluster-config",kind="Service",name="fortio/fortio-server-deployment-2-canary",object_namespace="fortio"} 1
k8sgpt_number_of_results_by_type{k8sgpt="k8sgpt-cluster-config",kind="Service",name="k8sgpt-operator-system/k8sgpt-k8sgpt-operat-controller-manager-metrics-service",object_namespace="k8sgpt-operator-system"} 1
k8sgpt_number_of_results_by_type{k8sgpt="k8sgpt-cluster-config",kind="Service",name="kube-system/kube-prometheus-stack-kube-controller-manager",object_namespace="kube-system"} 1
k8sgpt_number_of_results_by_type{k8sgpt="k8sgpt-cluster-config",kind="Service",name="kube-system/kube-prometheus-stack-kube-etcd",object_namespace="kube-system"} 1
k8sgpt_number_of_results_by_type{k8sgpt="k8sgpt-cluster-config",kind="Service",name="kube-system/kube-prometheus-stack-kube-scheduler",object_namespace="kube-system"} 1
k8sgpt_number_of_results_by_type{k8sgpt="k8sgpt-cluster-config",kind="StatefulSet",name="k8sgpt-operator-system/k8sgpt-interplex",object_namespace="k8sgpt-operator-system"} 1