Remove readonly on segment length property (Azure#16513)

specification/videoanalyzer/resource-manager/Microsoft.Media/preview/2021-11-01-preview/Videos.json

@@ -94,8 +94,7 @@
       "properties": {
         "segmentLength": {
           "type": "string",
-          "description": "Video segment length indicates the length of individual video files (segments) which are persisted to storage. Smaller segments provide lower archive playback latency but generate larger volume of storage transactions. Larger segments reduce the amount of storage transactions while increasing the archive playback latency. Value must be specified in ISO8601 duration format (i.e. \"PT30S\" equals 30 seconds) and can vary between 30 seconds to 5 minutes, in 30 seconds increments.",
-          "readOnly": true
+          "description": "Video segment length indicates the length of individual video files (segments) which are persisted to storage. Smaller segments provide lower archive playback latency but generate larger volume of storage transactions. Larger segments reduce the amount of storage transactions while increasing the archive playback latency. Value must be specified in ISO8601 duration format (i.e. \"PT30S\" equals 30 seconds) and can vary between 30 seconds to 5 minutes, in 30 seconds increments."
         }
       },
       "type": "object",
@@ -165,8 +164,7 @@
         },
         "mediaInfo": {
           "$ref": "#/definitions/VideoMediaInfo",
-          "description": "Contains information about the video and audio content.",
-          "readOnly": true
+          "description": "Contains information about the video and audio content."
         },
         "archival": {
           "$ref": "#/definitions/VideoArchival",