style(settings): adjust layout in service configuration view

Adds a `Spacer` to push the validation button to the bottom of the view. This creates better visual separation and a more balanced layout in the service configuration section.

Author: tisfeng

Easydict/Swift/View/SettingView/Tabs/ServiceConfigurationView/ServiceConfigurationSecretSectionView.swift

@@ -58,6 +58,8 @@ struct ServiceConfigurationSecretSectionView<Content: View>: View {
                 Spacer()
             }
 
+            Spacer()
+
             Button {
                 validate()
             } label: {