[dotnet] Fix error when we send non-base64 data for fetch command

[nvborisenko]

Description

I see a lot of exceptions while working with CDP. This PR fixes only one exception.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[nvborisenko]

Win! Now basics scenarios for network requests intercepting works.

Before:

driver.Manage().Network.StartMonitoring().Wait();

driver.Url = "https://google.com";

It throws many exceptions related to "Fetch" cdp domain.

Now we are able even do:

driver.Manage().Network.StartMonitoring().Wait();

net.AddRequestHandler(new NetworkRequestHandler
            {
                RequestMatcher = httpData => httpData.Url.Contains("google.com"),
                RequestTransformer = req =>
                {
                    req.Url = "https://selenium.dev";
                    return req;
                },
            });

driver.Url = "https://google.com"; // it opens selenium.dev instead of google.com

And even changing response body:

net.AddResponseHandler(new NetworkResponseHandler
            {
                ResponseMatcher = httpData => httpData.Url.Contains("google.com"),
                ResponseTransformer = res =>
                {
                    res.Body = "Hello World!";
                    return res;
                },
            });

[nvborisenko]

Still facing issue Invalid InterceptionId, but it is absolutely different story.

[diemol]

Thank you, @nvborisenko!