fix(pii): revert policy.go to upstream version to fix aibrix regression

The previous policy.go changes added a default_decision fallback mechanism
that broke aibrix profile. Aibrix uses static YAML config and doesn't have
a default_decision defined. Reverting to the upstream version from PR vllm-project#688
that passed aibrix tests successfully.

Related to vllm-project#648

Signed-off-by: Yossi Ovadia <[email protected]>

Author: yossiovadia

src/semantic-router/pkg/utils/pii/policy.go

@@ -14,10 +14,9 @@ type PolicyChecker struct {
 
 // IsPIIEnabled checks if PII detection is enabled for a given decision
 func (c *PolicyChecker) IsPIIEnabled(decisionName string) bool {
-	// If no decision specified, try to use the default catch-all decision
 	if decisionName == "" {
-		decisionName = "default_decision"
-		logging.Infof("No decision specified, trying default decision: %s", decisionName)
+		logging.Infof("No decision specified, PII detection disabled")
+		return false
 	}
 
 	decision := c.Config.GetDecisionByName(decisionName)
@@ -50,12 +49,6 @@ func (pc *PolicyChecker) CheckPolicy(decisionName string, detectedPII []string)
 		return true, nil, nil
 	}
 
-	// Apply same default decision fallback as in IsPIIEnabled
-	if decisionName == "" {
-		decisionName = "default_decision"
-		logging.Infof("No decision specified for CheckPolicy, trying default decision: %s", decisionName)
-	}
-
 	decision := pc.Config.GetDecisionByName(decisionName)
 	if decision == nil {
 		logging.Infof("Decision %s not found, allowing request", decisionName)