[fix/typo](JS/RN) Missing comma in Predictions IAM policy (aws-amplify#5349)

Author: Bannon Tanner

src/fragments/lib/predictions/js/getting-started.mdx

@@ -140,7 +140,7 @@ The Amplify CLI will set appropriate IAM policy for Roles in your Cognito Identi
         "comprehend:DetectSyntax",
         "comprehend:DetectKeyPhrases",
         "rekognition:DetectFaces",
-        "rekognition:RecognizeCelebrities"
+        "rekognition:RecognizeCelebrities",
         "rekognition:DetectLabels",
         "rekognition:DetectModerationLabels",
         "rekognition:DetectText",