[Due for payment 2025-07-18] [Due for payment 2025-07-14] [$500] Allow multiple workspaces selection in the `Workspaces` filter

[JmillsExpensify]

Description:

In research calls with admins, a long-standing request is the ability to filter report data from multiple workspaces at once. That's not currently possible in OldDot, and it was previously incompatible with NewDot. However, now that we're deprecating the workspace switcher, the backend already handles a list of workspaces, so we can open up selecting a list of workspaces in the front-end as well.

Proposal:

This proposal has three parts:

1. Make the workspace filter multi-select
   

2. Ensure the BE is fully compatible with FE multi-selection of workspaces

3. Add auto-complete for the workspace: search query

Special note: This issue will be held until Workspaces becomes a primary nav item and a related Reports project introduces new design patterns to filters. It's fine to post proposals ahead of this issue being taken off hold.

Issue Owner

Current Issue Owner: @JmillsExpensify

Issue Owner

Current Issue Owner: @luacmartins

[melvin-bot]

Triggered auto assignment to Contributor-plus team member for initial proposal review - @alitoshmatov (External)

[melvin-bot]

Triggered auto assignment to @bfitzexpensify (NewFeature), see https://stackoverflowteams.com/c/expensify/questions/14418#:~:text=BugZero%20process%20steps%20for%20feature%20requests for more details. Please add this Feature request to a GH project, as outlined in the SO.