add error handling, stderr output

sky/adaptors/azure.py

@@ -22,10 +22,21 @@
 
 
 def _get_account():
-    return json.loads(
-        run('az account show -o json',
-            stdout=subprocess.PIPE,
-            stderr=subprocess.DEVNULL).stdout.decode())
+    result = run('az account show -o json',
+                 stdout=subprocess.PIPE,
+                 stderr=subprocess.PIPE)
+
+    if result.returncode != 0:
+        error_message = result.stderr.decode()
+        print(f"Error executing command: {error_message}")
+        raise RuntimeError("Failed to execute 'az account show -o json' command.")
+
+    try:
+        return json.loads(result.stdout.decode())
+    except json.JSONDecodeError as e:
+        error_message = result.stderr.decode()
+        print(f"JSON parsing error: {e.msg}")
+        raise RuntimeError(f"Failed to parse JSON output. Error: {e.msg}\nCommand Error: {error_message}")
 
 
 def get_subscription_id() -> str: