Fix Windows RDP collectors startup

windows/browser-domains-native-collector.ps1

@@ -701,13 +701,26 @@ function Ensure-Bucket {
         return
     }
 
+    try {
+        Invoke-RestMethod -Method Get -Uri "$($script:ApiBase)/buckets/$BucketId" | Out-Null
+        $script:KnownBuckets[$BucketId] = $true
+        return
+    }
+    catch {
+    }
+
     $body = @{
         client   = $ClientName
         type     = $BucketType
         hostname = $script:Hostname
     } | ConvertTo-Json -Compress
 
-    Invoke-RestMethod -Method Post -Uri "$($script:ApiBase)/buckets/$BucketId" -ContentType 'application/json' -Body $body | Out-Null
+    try {
+        Invoke-RestMethod -Method Post -Uri "$($script:ApiBase)/buckets/$BucketId" -ContentType 'application/json; charset=utf-8' -Body ([Text.Encoding]::UTF8.GetBytes($body)) | Out-Null
+    }
+    catch {
+        Invoke-RestMethod -Method Get -Uri "$($script:ApiBase)/buckets/$BucketId" | Out-Null
+    }
     $script:KnownBuckets[$BucketId] = $true
 }