Fix import style and regenerate config file

- Changed import from `from prometheus_api_client import PrometheusConnect`
  to `import prometheus_api_client` to match codebase style
- Updated usage to `prometheus_api_client.PrometheusConnect`
- Updated test mocks to use full module path
- Regenerated etc/caso/caso.conf.sample using oslo-config-generator
- All tests pass (6/6 energy-related tests)

Co-authored-by: alvarolopez <468751+alvarolopez@users.noreply.github.com>

Author: Copilot

caso/extract/prometheus.py

@@ -18,7 +18,7 @@
 
 import uuid
 
-from prometheus_api_client import PrometheusConnect
+import prometheus_api_client
 from oslo_config import cfg
 from oslo_log import log
 
@@ -100,7 +100,9 @@ def _energy_consumed_wh(self, vm_uuid):
         query_range = CONF.prometheus.prometheus_query_range
         verify_ssl = CONF.prometheus.prometheus_verify_ssl
 
-        prom = PrometheusConnect(url=prom_url, disable_ssl=not verify_ssl)
+        prom = prometheus_api_client.PrometheusConnect(
+            url=prom_url, disable_ssl=not verify_ssl
+        )
 
         # factor = step_seconds / 3600 converts µW·s to µWh
         factor = step_seconds / 3600

caso/tests/extract/test_prometheus.py

@@ -93,7 +93,7 @@ def mock_prometheus_result_empty():
 class TestEnergyConsumptionExtractor:
     """Test the energy consumption extractor."""
 
-    @mock.patch("caso.extract.prometheus.PrometheusConnect")
+    @mock.patch("caso.extract.prometheus.prometheus_api_client.PrometheusConnect")
     def test_extract_with_results(
         self,
         mock_prom_connect,
@@ -144,7 +144,7 @@ def test_extract_with_no_vms(self, configured_extractor, extract_dates):
         # Verify - no VMs, no records
         assert len(records) == 0
 
-    @mock.patch("caso.extract.prometheus.PrometheusConnect")
+    @mock.patch("caso.extract.prometheus.prometheus_api_client.PrometheusConnect")
     def test_extract_with_no_energy_data(
         self,
         mock_prom_connect,
@@ -170,7 +170,7 @@ def test_extract_with_no_energy_data(
         assert len(records) == 0
 
     @mock.patch("caso.extract.prometheus.LOG")
-    @mock.patch("caso.extract.prometheus.PrometheusConnect")
+    @mock.patch("caso.extract.prometheus.prometheus_api_client.PrometheusConnect")
     def test_extract_with_prometheus_exception(
         self,
         mock_prom_connect,