PR Summary

In the early parsing code, a null switchkey can be returned. This isn't expected in later code resulting in an unhandled exception. Fix is to check if switchkey is null before additoinal processing. In this case, just whitespace is sent to PowerShell whereas an empty string returns an error.

PR Context

Fix #10975

PR Checklist

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    • Impact on PowerShell Editor Services which is used in the PowerShell extension for VSCode (which runs in a different PS Host).
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