Timeline date selection centering functionality (#1181)

**Related Ticket:**
https://github.com/orgs/NASA-IMPACT/projects/17/views/6?pane=issue&itemId=74641280

### Description of Changes
_{Update with description of changes made in this pull request}_

### Notes & Questions About Changes
This ticket introduces `centerTimelineOnSelections` function. 

### Validation / Testing
Navigate to exploration and select a data set. This functionality should
only center when dates are selected from the date selector at the top.
No centering functionality should be visible when a date in the timeline
is selected via the click and drag interface.

**Single date selection:** Select a date that is outside of the current
timeline view from the date picker. The timeline should pan to have that
newly selected date now centered in the timeline.

**Comparison date selection:** Select a date that is outside of the
current timeline view from the date picker. The timeline should pan &
zoom to have that newly selected date range now centered in the
timeline.

Select an 'A' date that is later in time than the existing 'B' date and
then pan should still center around the 2 items.