mayaUSDExport resolves away uri's passed into file

When calling the maya command: mayaUSDExport with a uri, the uri is immediately resolved and not used to write changes. This can be worked around by calling `file -exportAll -type "USD Export" uri` which does not resolve the uri and passes it down to USD.

**Steps to reproduce**
Steps to reproduce the behavior:
cmds.mayaUSDExport(file="http://path/to/my.usd")

You'll see the output from USD save writes the resolved file like "c:/path/to/my.usd" instead of "http://path/to/my.usd"

**Expected behavior**
cmds.file("http://path/to/my.usd", exportAll=True, type="USD Export")

You'll see the output from USD save writes "http://path/to/my.usd"

**Additional context**
Will need to make an MPxFileResolver to see the behavior

It looks like file doesn't need to be resolved, but maybe the code is there for another purpose that should also be considered:
https://github.com/Autodesk/maya-usd/blob/207bb11cc10b37251a07ce346347ed41314065b9/lib/mayaUsd/commands/baseExportCommand.cpp#L287