Google Safe Browsing v5

Hi,

I am testing the google-apis-safebrowsing_v5 gem, and i got nil as result.
idk if i am doing something wrong.

This is my simple example
```ruby
client = Google::Apis::SafebrowsingV5::SafebrowsingService.new
client.request_options.header ||= {}
client.request_options.header['Referer'] = 'http://localhost'
client.key = ENV.fetch("GOOGLE_SAFE_LINK_KEY")
r = client.search_hashes(hash_prefixes: ['BQRvJg'])
puts "GEM RESULT: #{r}"
```

I tested in Postman, it returns me 200 ( and i think gem did it as well )

I also Isolated the issue in my GH repo: https://github.com/alexcastrodev/safe-browsing-v5-protobuf-issue

Appreciate community help