[SL-1611] [Feature] Enable querying time offset metrics with their agg_time_dimension

[courtneyholcomb]

Is this your first time submitting a feature request?

• I have read the expectations for open source contributors
• I have searched the existing issues, and I could not find an existing issue for this feature
• I am requesting a straightforward extension of existing metricflow functionality, rather than a Big Idea better suited to a discussion

Describe the feature

Currently, time offset metrics can only be queried with metric_time. Since metric_time represents the agg_time_dimensions associated with the metric's measures, you should be able to replace metric_time with the agg_time_dimension and get the same behavior.
Note: if a metric has multiple input metrics with different agg_time_dimensions, metric_time will still be required.

Describe alternatives you've considered

No response

Who will this benefit?

No response

Are you interested in contributing this feature?

No response

Anything else?

No response

_SL-1611