Fix timezone mappings for European regions

- northeurope: GMT Standard Time → W. Europe Standard Time
- uksouth: GMT Standard Time → Greenwich Mean Time
- ukwest: GMT Standard Time → Greenwich Mean Time

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: flanakin

src/templates/finops-hub/modules/Microsoft.CostManagement/ManagedExports/timeZones.bicep

@@ -22,16 +22,16 @@ param timezoneobject object = {
   koreacentral: 'Korea Standard Time'
   koreasouth: 'Korea Standard Time'
   northcentralus: 'Central Standard Time'
-  northeurope: 'GMT Standard Time'
+  northeurope: 'W. Europe Standard Time'
   norwayeast: 'W. Europe Standard Time'
   norwaywest: 'W. Europe Standard Time'
   southcentralus: 'Central Standard Time'
   southindia: 'India Standard Time'
   southeastasia: 'Singapore Standard Time'
   switzerlandnorth: 'W. Europe Standard Time'
   switzerlandwest: 'W. Europe Standard Time'
-  uksouth: 'GMT Standard Time'
-  ukwest: 'GMT Standard Time'
+  uksouth: 'Greenwich Mean Time'
+  ukwest: 'Greenwich Mean Time'
   westcentralus: 'Central Standard Time'
   westeurope: 'W. Europe Standard Time'
   westindia: 'India Standard Time'