Add System.Text.Encodings.Web dep for json context

Author: nvborisenko

dotnet/src/webdriver/BUILD.bazel

@@ -55,6 +55,7 @@ csharp_library(
         framework("nuget", "Microsoft.Bcl.AsyncInterfaces"),
         framework("nuget", "System.Threading.Tasks.Extensions"),
         framework("nuget", "System.Memory"),
+        framework("nuget", "System.Text.Encodings.Web"),
         framework("nuget", "System.Text.Json"),
     ],
 )
@@ -119,6 +120,7 @@ csharp_library(
         framework("nuget", "Microsoft.Bcl.AsyncInterfaces"),
         framework("nuget", "System.Threading.Tasks.Extensions"),
         framework("nuget", "System.Memory"),
+        framework("nuget", "System.Text.Encodings.Web"),
         framework("nuget", "System.Text.Json"),
     ],
 )