Error message when API calls fail due to an untrusted certificate should be made more clear

When the API calls fail due to an untrusted certificate, the error message implies it is related to authentication. The user may then follow the steps outlined in [Authenticating with Gradle Enterprise](https://github.com/gradle/gradle-enterprise-build-validation-scripts/blob/main/Gradle.md#authenticating-with-gradle-enterprise) when really they should be following [Configuring the network settings to connect to Develocity](https://github.com/gradle/gradle-enterprise-build-validation-scripts/blob/main/Gradle.md#configuring-the-network-settings-to-connect-to-develocity).

In these scenarios, an exception related to the untrusted certificate is thrown. We should catch that and display a different error message rather than the generic authentication one.