Elevation action is case sensitive

[alan-null]

Steps:

Configure any gate with elevation action using uppercase.

Actual result:
Elevation action is case sensitive - not parsed correctly unless you specify it explicitly.

Expected result:
Elevation action is case insensitive

Related code:
https://github.com/SitecorePowerShell/Console/blob/master/src/Spe/Core/Settings/Authorization/SessionElevationManager.cs#L39

POC