Fix a panic during wwctl node list --ipmi for nodes with no ipmi configuration. #1847

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

internal/app/wwctl/node/list/main_test.go

@@ -187,6 +187,18 @@ nodes:
     profiles:
     - default
 `,
+		},
+		{
+			name:    "node list with no ipmi data",
+			args:    []string{"--ipmi"},
+			wantErr: false,
+			stdout: `
+NODE  IPMI IPADDR  IPMI PORT  IPMI USERNAME  IPMI INTERFACE
+----  -----------  ---------  -------------  --------------
+n1    --           --         --             --`,
+			inDb: `
+nodes:
+  n1: {}`,
 		},
 		{
 			name:    "node list profile with ipmi user",