fix(core): Filter null or empty string from Scoops directory settings

lib/core.ps1

@@ -838,14 +838,18 @@ function get_magic_bytes_pretty($file, $glue = ' ') {
 #       for all communication with api.github.com
 Optimize-SecurityProtocol
 
-$scoopdir = $env:SCOOP, (get_config 'rootPath'), "$env:USERPROFILE\scoop" | Select-Object -first 1
-$globaldir = $env:SCOOP_GLOBAL, (get_config 'globalPath'), "$env:ProgramData\scoop" | Select-Object -first 1
+# Scoop root directory
+$scoopdir = $env:SCOOP, (get_config 'rootPath'), "$env:USERPROFILE\scoop" | Where-Object { -not [String]::IsNullOrEmpty($_) } | Select-Object -First 1
 
+# Scoop global apps directory
+$globaldir = $env:SCOOP_GLOBAL, (get_config 'globalPath'), "$env:ProgramData\scoop" | Where-Object { -not [String]::IsNullOrEmpty($_) } | Select-Object -first 1
+
+# Scoop cache directory
 # Note: Setting the SCOOP_CACHE environment variable to use a shared directory
 #       is experimental and untested. There may be concurrency issues when
 #       multiple users write and access cached files at the same time.
 #       Use at your own risk.
-$cachedir = $env:SCOOP_CACHE, (get_config 'cachePath'), "$scoopdir\cache" | Select-Object -first 1
+$cachedir = $env:SCOOP_CACHE, (get_config 'cachePath'), "$scoopdir\cache" | Where-Object { -not [String]::IsNullOrEmpty($_) } | Select-Object -first 1
 
 # Scoop config file migration
 $configHome = $env:XDG_CONFIG_HOME, "$env:USERPROFILE\.config" | Select-Object -First 1