[dotnet] [bidi] Remove NavigateBack and NavigateForward as not a part… (#16068)

[dotnet] [bidi] Remove NavigateBack and NavigateForward as not a part of low level

Author: nvborisenko

dotnet/src/webdriver/BiDi/BrowsingContext/BrowsingContext.cs

@@ -91,16 +91,6 @@ public Task TraverseHistoryAsync(int delta, TraverseHistoryOptions? options = nu
  return BiDi.BrowsingContext.TraverseHistoryAsync(this, delta, options);
  }
 
- public Task NavigateBackAsync(TraverseHistoryOptions? options = null)
- {
- return TraverseHistoryAsync(-1, options);
- }
-
- public Task NavigateForwardAsync(TraverseHistoryOptions? options = null)
- {
- return TraverseHistoryAsync(1, options);
- }
-
  public Task SetViewportAsync(SetViewportOptions? options = null)
  {
  return BiDi.BrowsingContext.SetViewportAsync(this, options);