Add FindingSubject.__str__ (#523)

This is important for the PagerDuty sink where we convert the FindingSubject to string. We should have a standard representation for it.

helm/robusta/values.yaml

@@ -126,6 +126,7 @@ builtinPlaybooks:
 - triggers:
   - on_prometheus_alert:
       alert_name: CPUThrottlingHigh
+      status: "all" # sometimes this enricher silences the alert, so we need to silence it regardless of status
   actions:
   - cpu_throttling_analysis_enricher: {}
   - alert_graph_enricher:

src/robusta/core/reporting/base.py

@@ -110,6 +110,11 @@ def __init__(
         self.namespace = namespace
         self.node = node
 
+    def __str__(self):
+        if self.namespace is not None:
+            return f"{self.namespace}/{self.subject_type.value}/{self.name}"
+        return f"{self.subject_type.value}/{self.name}"
+
 
 class Finding(Filterable):
     """