Use more accurate user-agent header

Initial patch.

We can set Framework name and Framework version via methods:

   GatherContentClientInterface::setFrameworkName('Drupal');
   GatherContentClientInterface::setFrameworkVersion(\Drupal::VERSION);

But it seems like the integration version needs to be a constant

GatherContentClientInterface::INTEGRATION_VERSION

The proposed patch results in this user agent:

user-agent: "Integration-Drupal-10.1.4/6.1.0"

We extend the class, so we can just override getVersionString() or getIntegrationVersion()?

The requested string was Integration-Drupal-/Drupal Plugin Version

We actually have 3 version numbers, the drupal version, the module version, and the version of the comonent (the constant). I will ask for confirmation if we should include all 3 version numbers and in which format.

Yes, we could also just extend that method. Would make even more sense if including all 3 is needed.

As per discussion, overriding the method. If the version is not available, then do we output something like `user-agent: "Integration-Drupal-10.1.4/dev"` (current patch) or core version?

Forgot to revert the service.yml change.

dev seems fine, committed.

Automatically closed - issue fixed for 2 weeks with no activity.