Added workspace Id tracking

[JR-Morgan]

This PR adds workspace_id tracking for Receive and Send events.

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I was going to add support for fetching the workspace id to all of the ProjectResource queries, like I've done for the v3 sdk https://github.com/specklesystems/speckle-sharp-sdk/pull/134

But, since its important that the v2 SDK is compatible with older self hosted servers, I thought it would be easiest simply to add a helper function just for this query. This avoids having to add a version check in each of the Project resources (which, at least right now in their current form don't have direct access to the underlying GqlClient.

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Needs through testing:

• Test with app.speckle.systems:

  • [x] project on a workspace, does it track send and receives in mixpanel
  • [x] project not on a workspace, should track null

• Test with testing1

  • [x] project not on a workspace, should track null, nothing should throw!

[linear[bot]]

CXPLA-96 Update SDKs to add new Workspaces properties

[didimitrie]

note: didn't test locally, just sanity check glanced at the code!