minor changes to swagger (Azure#12253)

* minor changes to swagger

* reverting sdk definitions file

Author: hivyas

specification/mediaservices/data-plane/LiveVideoAnalytics.Edge/preview/2.0.0/LiveVideoAnalytics.json

@@ -425,7 +425,8 @@
         }
       },
       "required": [
-        "username"
+        "username",
+        "password"
       ],
       "allOf": [
         {
@@ -910,9 +911,6 @@
     },
     "MediaGraphImageScale": {
       "type": "object",
-      "required": [
-        "mode"
-      ],
       "properties": {
         "mode": {
           "type": "string",