Fix typo in playlist url

spec/helpers_spec.cr

@@ -34,7 +34,7 @@ describe "Helper" do
 
   describe "#produce_channel_playlists_url" do
     it "correctly produces a /browse_ajax URL with the given UCID and cursor" do
-      produce_channel_playlists_url("UCCj956IF62FbT7Gouszaj9w", "AIOkY9EQpi_gyn1_QrFuZ1reN81_MMmI1YmlBblw8j7JHItEFG5h7qcJTNd4W9x5Quk_CVZ028gW").should eq("/browse_ajax?continuation=4qmFsgLJARIYVUNDajk1NklGNjJGYlQ3R291c3phajl3GqwBRWdod2JHRjViR2x6ZERBQ09BRmdBV29BdUFFQWVtWlJWV3hRWVRGck5WSldSbmRoVmpsdVpWYzBlRmd4Um5sU2JsWmhUVmhLYkZScVozaFlNREZPWWxWcmVGZFhNWE5SYlVwelpIcG9jVTR3Y0VsVFdGSkdVbXRqTVdGRVpIaFpNSEJWVkcxUk1GWjZiRFJPVmtZeFlURTVSRlpzYjNkTmFtaHVWbmNnQVJnRA%3D%3D&gl=US&hl=en")
+      produce_channel_playlists_url("UCCj956IF62FbT7Gouszaj9w", "AIOkY9EQpi_gyn1_QrFuZ1reN81_MMmI1YmlBblw8j7JHItEFG5h7qcJTNd4W9x5Quk_CVZ028gW").should eq("/browse_ajax?continuation=4qmFsgLNARIYVUNDajk1NklGNjJGYlQ3R291c3phajl3GrABRWdsd2JHRjViR2x6ZEhNd0FqZ0JZQUZxQUxnQkFIcG1VVlZzVUdFeGF6VlNWa1ozWVZZNWJtVlhOSGhZTVVaNVVtNVdZVTFZU214VWFtZDRXREF4VG1KVmEzaFhWekZ6VVcxS2MyUjZhSEZPTUhCSlUxaFNSbEpyWXpGaFJHUjRXVEJ3VlZSdFVUQldlbXcwVGxaR01XRXhPVVJXYkc5M1RXcG9ibFozSUFFWUF3PT0%3D&gl=US&hl=en")
     end
   end
 

src/invidious/channels.cr

@@ -484,7 +484,7 @@ def produce_channel_playlists_url(ucid, cursor, sort = "newest", auto_generated
     "80226972:embedded" => {
       "2:string" => ucid,
       "3:base64" => {
-        "2:string" => "playlist",
+        "2:string" => "playlists",
         "6:varint":   2_i64,
         "7:varint":   1_i64,
         "12:varint":  1_i64,