Update Usage Ping Metrics Definitions for group::license

What does this MR do?

Update grouplicense related usage ping metric definitions.

Add new data_source "license" (see #322557 (comment 594155784))

Correction:

• Move license_trial_ends_on to ee
• Update product group

No changelog as this isn't user facing.

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Related to #322708 (closed)