Trim whitespace from the identity server text entry and don't allow an empty string.

Riot/Modules/Settings/IdentityServer/SettingsIdentityServerViewController.swift

@@ -345,7 +345,12 @@ final class SettingsIdentityServerViewController: UIViewController {
     private func addOrChangeAction() {
         self.identityServerTextField.resignFirstResponder()
 
-        guard let displayMode = self.displayMode, let identityServer = self.identityServerTextField.text else {
+        guard
+            let displayMode = displayMode,
+            let identityServer = identityServerTextField.text?.trimmingCharacters(in: .whitespaces),
+            !identityServer.isEmpty
+        else {
+            viewModel.process(viewAction: .load)
             return
         }