CSP's nonce support for ReCaptchaBuilderV3

[moijafcor]

Refactoring htmlScriptTagJsApi() method to provide basic support for CSP's nonce tag.

Leveraging the $configuration optional parameter to inject a nonce attribute in the inline Javascript tag.

The way to use this, on your Blade's (assuming you are using https://github.com/spatie/laravel-csp or something else that generates the nonce):

{{-- "csp_nonce()" in this case is provided by https://github.com/spatie/laravel-csp --}}
{!! \ReCaptcha::htmlScriptTagJsApi(['nonce' => csp_nonce()]) !!}

[moijafcor]

Fixing missing checking for array key null value.