Remove total counts for snowplow events in usage ping

What does this MR do?

In usage ping, stop reporting total counts for snowplow events for two reasons:

1. Since we have no retention policy right now, the amount of data we query is unbounded
2. Once we do have a retention policy, the numbers reported will not be "totals" anymore

This is not a breaking change, since we only have one event being reported for testing purposes, and no charts have been created off of it.

After this change, snowplow events will only appear under counts_monthly.

A changelog is omitted because reporting of snowplow events is behind the product_analytics FF, which is disabled by default.

/cc @jeromezng

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• [-] Separation of EE specific content

Availability and Testing

• [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team