chore(monitoring): tidy GPU VMRule top-level structure

Drop the hardcoded metadata.namespace so the rule inherits the chart's
release namespace, and add an explicit empty params field on every
group for schema consistency. No behavior change.

Signed-off-by: Arsolitt <arsolitt@gmail.com>

packages/system/monitoring-agents/alerts/gpu-recording.rules.yaml

@@ -2,11 +2,11 @@ apiVersion: operator.victoriametrics.com/v1beta1
 kind: VMRule
 metadata:
   name: alerts-gpu-recording.rules
-  namespace: cozy-monitoring
 spec:
   groups:
     - name: gpu.recording.cluster.1m
       interval: 1m
+      params: {}
       rules:
         - record: cluster:gpu_count:total
           expr: count(group by (UUID) (DCGM_FI_DEV_GPU_UTIL))
@@ -25,6 +25,7 @@ spec:
 
     - name: gpu.recording.namespace.1m
       interval: 1m
+      params: {}
       rules:
         # Kube-requested GPU count per namespace — billable view, includes
         # Pending pods. Use this for GPU-hour reporting via
@@ -61,6 +62,7 @@ spec:
 
     - name: gpu.recording.efficiency.1m
       interval: 1m
+      params: {}
       rules:
         # Tensor hardware saturation — the honest "am I using the GPU" metric
         # for AI/LLM workloads. Unlike NVML, idle tensor cores are visible.