Better reporting for CKEditor 4 vs 5 in Telemetry

Description of the need

Follow-up from https://github.com/backdrop/backdrop-issues/issues/4122.

Right now both CKEditor 4 and CKEditor 5 modules implement hook_telemetry_info() to report their respective CKEditor version strings. For example:

CKEditor 4 returns ckeditor_version of 4.18.0 CKEditor 5 returns ckeditor5_version of 40.2.0

While this data is useful in some ways to tell how up-to-date our library usage is, it's not helpful for distinguishing between CKEditor 4 and 5 (or both) usage. To do that we need a separate return value of either 4, 5, or both.

Proposed solution

Since each module can only report if it is enabled, I think it would make sense to include this value in telemetry.module directly.