Fix content-type in examples for ACS AUTH REST API version 2020-07-20-preview2 and 2021-03-07 (#13036)

Co-authored-by: Alexandra Lamiova Pistrakova <[email protected]>

Author: alexandra142

specification/communication/data-plane/Microsoft.CommunicationServicesIdentity/preview/2020-07-20-preview2/examples/IssueToken.json

@@ -1,7 +1,7 @@
 {
   "parameters": {
     "api-version": "2020-07-20-preview2",
-    "content-type": "application/merge-patch+json",
+    "content-type": "application/json",
     "id": "8:acs:2dee53b4-368b-45b4-ab52-8493fb117652_00000005-14a2-493b-8a72-5a3a0d000081",
     "body": {
       "scopes": [

specification/communication/data-plane/Microsoft.CommunicationServicesIdentity/stable/2021-03-07/examples/IssueAccessToken.json

@@ -1,7 +1,7 @@
 {
   "parameters": {
     "api-version": "2021-03-07",
-    "content-type": "application/merge-patch+json",
+    "content-type": "application/json",
     "id": "8:acs:2dee53b4-368b-45b4-ab52-8493fb117652_00000005-14a2-493b-8a72-5a3a0d000081",
     "body": {
       "scopes": [