'Select PSScriptAnalyzer rules' command broke starting with preview extension 2019.11.0

Using 2020.1.0 but I have seen it before the recent update. Going back to previous release, I found that 2019.9.0 was the last version where it still worked therefore it something in between 2019.9.0 and 2019.11.0 ,which is likely going to be the omnisharp refactoring @TylerLeonhardt

System Details Output

### VSCode version: 1.42.0-insider 33c79d5ad447956814a2a3658029dffb9e28bae6 x64

### VSCode extensions:
DavidAnson.vscode-markdownlint@0.33.0
eamodio.gitlens@10.2.0
mauve.terraform@1.4.0
ms-azure-devops.azure-pipelines@1.157.4
ms-azuretools.vscode-azureappservice@0.16.2
ms-azuretools.vscode-azurefunctions@0.20.1
ms-azuretools.vscode-azurestorage@0.7.2
ms-azuretools.vscode-azureterraform@0.3.0
ms-azuretools.vscode-docker@0.9.0
ms-python.python@2020.1.58038
ms-vscode-remote.remote-containers@0.97.0
ms-vscode-remote.remote-wsl@0.42.1
ms-vscode.azure-account@0.8.8
ms-vscode.csharp@1.21.9
ms-vscode.powershell@2020.1.0
ms-vscode.powershell-preview@2020.1.0
ms-vsonline.vsonline@1.0.1424
msazurermtools.azurerm-vscode-tools@0.8.3
samcogan.arm-snippets@1.4.19


### PSES version:

### PowerShell version:

Name                           Value
----                           -----
PSVersion                      7.0.0-rc.1
PSEdition                      Core
GitCommitId                    7.0.0-rc.1
OS                             Microsoft Windows 10.0.18362
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Issue Description

Open a PowerShell file to start the extension.
When selecting the 'Select PSScriptAnalyzer rules' nothing happens

Expected Behaviour

A dropdown menu of PSSA rules should come up.

Actual Behaviour

Nothing happens

Reproduce the failure by opening a PowerShell file and running “Select PSScriptAnalyzer rules” in the extension, comparing releases 2019.9.0 and 2019.11.0. Inspect the command path and the suspected OmniSharp refactoring change mentioned in the issue. Done means the PSScriptAnalyzer rules dropdown appears as expected.