Remove (Preview) label from GA features

[kburtram]

Steps to Reproduce:

1. Connection dialog still says "(Preview)"

Expected: This should be removed for May. Since main is already targeting May release, this should be done anytime.

Note: It would be good to do this for all Connection, Table Designer, OE Filtering, Query Results, and Query Plan UI. Also we should make these features no longer gated on the "rich UX" or other preview flags. I'll open individual bugs for each feature next week if needed.

[Benjin]

I'll use this as the task to do the full Preview -> GA swapover