Adding the missing 'required' attribute present in preview APIs and not in the GA version (#18946)

* Adding the missing 'required' attribute present in preview APIs and not in the GA version

* Updates

Author: bidisha-c

specification/cognitiveservices/data-plane/Language/stable/2022-05-01/textanalytics.json

@@ -1406,6 +1406,9 @@
           "$ref": "#/definitions/AnalyzeTextTaskResult"
         }
       ],
+      "required": [
+        "results"
+      ],
       "x-ms-discriminator-value": "EntityRecognitionResults"
     },
     "EntitiesResult": {
@@ -1532,6 +1535,9 @@
           "$ref": "#/definitions/AnalyzeTextTaskResult"
         }
       ],
+      "required": [
+        "results"
+      ],
       "x-ms-discriminator-value": "EntityLinkingResults"
     },
     "EntityLinkingResult": {
@@ -1698,6 +1704,9 @@
           "$ref": "#/definitions/AnalyzeTextTaskResult"
         }
       ],
+      "required": [
+        "results"
+      ],
       "x-ms-discriminator-value": "PiiEntityRecognitionResults"
     },
     "PiiResult": {
@@ -1997,6 +2006,9 @@
           "$ref": "#/definitions/AnalyzeTextTaskResult"
         }
       ],
+      "required": [
+        "results"
+      ],
       "x-ms-discriminator-value": "KeyPhraseExtractionResults"
     },
     "KeyPhraseResult": {
@@ -2064,6 +2076,9 @@
           "$ref": "#/definitions/AnalyzeTextTaskResult"
         }
       ],
+      "required": [
+        "results"
+      ],
       "x-ms-discriminator-value": "LanguageDetectionResults"
     },
     "LanguageDetectionResult": {