Update px api-key create and px get cluster to write to stdout

Summary: These commands in particular are used to pipe the output as variables to downstream tools, so we should write to stdout.

Test Plan: Run commands with bazel.

Reviewers: vihang

Reviewed By: vihang

Signed-off-by: Michelle Nguyen <michellenguyen@pixielabs.ai>

Differential Revision: https://phab.corp.pixielabs.ai/D11521

GitOrigin-RevId: f362601

src/pixie_cli/pkg/cmd/api_key.go

@@ -84,7 +84,7 @@ var CreateAPIKeyCmd = &cobra.Command{
 			log.WithError(err).Fatal("Failed to generate API key")
 		}
 		if short {
-			utils.Infof(key)
+			fmt.Fprintf(os.Stdout, "%s\n", key)
 		} else {
 			utils.Infof("Generated API key: \nID: %s \nKey: %s", keyID, key)
 		}

src/pixie_cli/pkg/cmd/get.go

@@ -171,12 +171,12 @@ var GetClusterCmd = &cobra.Command{
 		cloudAddr := vizier.GetCloudAddrFromKubeConfig(config)
 
 		if id {
-			cliUtils.Infof("%s", clusterID)
+			fmt.Fprintf(os.Stdout, "%s\n", clusterID)
 			return
 		}
 
 		if addr {
-			cliUtils.Infof("%s", cloudAddr)
+			fmt.Fprintf(os.Stdout, "%s\n", cloudAddr)
 			return
 		}