Fix: resolved issue sending pipes from Revit

[EuanKeyframe]

Description & motivation

When attempting to upload a model from Revit using the connector, it was failing when attempting to upload certain pipe objects. We managed to isolate the pipe elements and attempt to upload them in isolation. When we tried this we were getting "Object reference not set to an instance of an object" errors. Upon debugging the connector locally. We found this error was occuring when creating RevitPipe objects. When setting the systemName value an error was occuring as there was no MEPSystem associated with the pipe. To fix this we added a null check against the MEPSystem of the revitPipe object. If the MEPSystem doesnt exist the systemName defaults to an empty string.

Fixes #3551

Changes:

Added a null coalescing check when adding systemName value when creating RevitPipe objects. This allows pipes to be creating and sent to Speckle if not connected to a MEPSystem.

Screenshots:

Validation of changes:

Checklist:

• My pull request follows the guidelines in the Contributing guide?
• My pull request does not duplicate any other open Pull Requests for the same update/change?
• My commits are related to the pull request and do not amend unrelated code or documentation.
• My code follows a similar style to existing code.

References

Issue: #3559
Forum Post: https://speckle.community/t/revit-pipes-failing-to-export/10139

[connorivy]

Looks good! Thanks for the PR