PSModule-Helpers.ps1 is not removing some module imports

Some module imports during image generation [use two backslashes in the path](https://github.com/actions/virtual-environments/blob/main/images/win/scripts/Installers/Install-AzureModules.ps1#L7)... In cases like this the PSModule-Helpers does not match these paths because it's checking for paths that start with a single backslash.

PSModule-Helpers.ps1 should resolve paths it encounters and then process exclusions. This will mitigate the problem of multiple backslashes entries in `$env:PSModulePath`

Found while working on https://github.com/Azure/azure-sdk-for-cpp/pull/3482/files