Update owners for Form Recognizer (#23241)

Author: bojunehsu

CODEOWNERS

@@ -64,6 +64,9 @@
 # PRLabel: %Cognitive Services
 /specification/cognitiveservices/ @felixwa @yangyuan
 
+# PRLabel: %Cognitive Services - Form Recognizer
+/specification/cognitiveservices/data-plane/FormRecognizer/ @bojunehsu @nizi1127 @johanste
+
 # PRLabel: %Cognitive - Language
 /specification/cognitiveservices/data-plane/Language/ @assafi @rokulka @ChongTang @annatisch @heaths @deyaaeldeen @kristapratico @mssfang @joseharriaga @Azure/api-stewardship-board