fix(azure): make location optional for spot allocation

- Restore DefaultHostingPlace() to return nil, nil when no location env
  is set, with an info-level log instead of a hard error
- Requiring location at mc.Init() broke spot workflows that don't need
  it (fixes #839); the non-spot path in allocation.go already enforces
  location explicitly when missing

Co-Authored-By: Claude <Sonnet 4.6> <noreply@anthropic.com>
Signed-off-by: Rishabh Kothari <rkothari@redhat.com>

Author: rishupk

pkg/provider/azure/azure.go

@@ -42,7 +42,8 @@ func (a *Azure) DefaultHostingPlace() (*string, error) {
 	if len(hp) > 0 {
 		return &hp, nil
 	}
-	return nil, fmt.Errorf("missing default value for Azure Location, set ARM_LOCATION_NAME or AZURE_DEFAULTS_LOCATION environment variable")
+	logging.Infof("missing default value for Azure Location, if needed it should set using ARM_LOCATION_NAME or AZURE_DEFAULTS_LOCATION")
+	return nil, nil
 }
 
 // Envs required for auth with go sdk