configureHTTP2 methods default read idle timeout is an absolute pain when dealing with androidpublisher service.

#### Environment details

- Programming language: golang
- OS: linux
- Language runtime version: 1.25
- Package version: v0.267.0

#### Steps to reproduce
```
gcpcreds := option.WithCredentialsJSON(envx.Base64([]byte("{}"), _eg.EnvUnsafeGcloudADCB64))
scopes := option.WithScopes(androidpublisher.AndroidpublisherScope)

client, endpoint, err := htransport.NewClient(ctx, gcpcreds, dialer, keepalive, scopes)
if err != nil {
return err
}

service, err := androidpublisher.NewService(ctx, option.WithHTTPClient(client), option.WithEndpoint(endpoint))
if err != nil {
return fmt.Errorf("play store init failed: %w", err)
}
```
configureHTTP2 hardcodes the timeout to 31 seconds and the client which htransport.NewClient returns is impossible to configure. as a result one has to entirely configure a http client manually, which is awful.