FlowStepPage: make `onBackClicked` nullable and remove `canGoBack`.

features/logout/impl/src/main/kotlin/io/element/android/features/logout/impl/LogoutView.kt

@@ -58,7 +58,6 @@ fun LogoutView(
     val eventSink = state.eventSink
 
     FlowStepPage(
-        canGoBack = true,
         onBackClicked = onBackClicked,
         title = title(state),
         subTitle = subtitle(state),

features/securebackup/impl/src/main/kotlin/io/element/android/features/securebackup/impl/disable/SecureBackupDisableView.kt

@@ -56,7 +56,6 @@ fun SecureBackupDisableView(
     }
     FlowStepPage(
         modifier = modifier,
-        canGoBack = true,
         onBackClicked = onBackClicked,
         title = stringResource(id = R.string.screen_key_backup_disable_title),
         subTitle = stringResource(id = R.string.screen_key_backup_disable_description),

features/securebackup/impl/src/main/kotlin/io/element/android/features/securebackup/impl/enable/SecureBackupEnableView.kt

@@ -46,7 +46,6 @@ fun SecureBackupEnableView(
     }
     FlowStepPage(
         modifier = modifier,
-        canGoBack = true,
         onBackClicked = onBackClicked,
         title = stringResource(id = R.string.screen_chat_backup_key_backup_action_enable),
         iconResourceId = CommonDrawables.ic_key,

features/securebackup/impl/src/main/kotlin/io/element/android/features/securebackup/impl/enter/SecureBackupEnterRecoveryKeyView.kt

@@ -50,7 +50,6 @@ fun SecureBackupEnterRecoveryKeyView(
 
     FlowStepPage(
         modifier = modifier,
-        canGoBack = true,
         onBackClicked = onBackClicked,
         iconResourceId = CommonDrawables.ic_key,
         title = stringResource(id = R.string.screen_recovery_key_confirm_title),

features/securebackup/impl/src/main/kotlin/io/element/android/features/securebackup/impl/setup/SecureBackupSetupView.kt

@@ -48,8 +48,7 @@ fun SecureBackupSetupView(
 ) {
     FlowStepPage(
         modifier = modifier,
-        canGoBack = state.canGoBack(),
-        onBackClicked = onBackClicked,
+        onBackClicked = onBackClicked.takeIf { state.canGoBack() },
         title = title(state),
         subTitle = subtitle(state),
         iconResourceId = CommonDrawables.ic_key,

libraries/designsystem/src/main/kotlin/io/element/android/libraries/designsystem/atomic/pages/FlowStepPage.kt

@@ -40,7 +40,7 @@ import io.element.android.libraries.theme.ElementTheme
 
 /**
  * A Page with:
- * - a top bar as TobAppBar with optional back button
+ * - a top bar as TobAppBar with optional back button (displayed if [onBackClicked] is not null)
  * - a header, as IconTitleSubtitleMolecule
  * - a content.
  * - a footer, as ButtonColumnMolecule
@@ -48,24 +48,23 @@ import io.element.android.libraries.theme.ElementTheme
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun FlowStepPage(
-    canGoBack: Boolean,
-    onBackClicked: () -> Unit,
     iconResourceId: Int?,
     title: String,
     modifier: Modifier = Modifier,
+    onBackClicked: (() -> Unit)? = null,
     subTitle: String? = null,
     content: @Composable () -> Unit = {},
     buttons: @Composable ColumnScope.() -> Unit = {},
 ) {
-    BackHandler(enabled = canGoBack) {
-        onBackClicked()
+    BackHandler(enabled = onBackClicked != null) {
+        onBackClicked?.invoke()
     }
     HeaderFooterPage(
         modifier = modifier,
         topBar = {
             TopAppBar(
                 navigationIcon = {
-                    if (canGoBack) {
+                    if (onBackClicked != null) {
                         BackButton(onClick = onBackClicked)
                     }
                 },
@@ -94,7 +93,6 @@ fun FlowStepPage(
 @Composable
 internal fun FlowStepPagePreview() = ElementPreview {
     FlowStepPage(
-        canGoBack = true,
         onBackClicked = {},
         title = "Title",
         subTitle = "Subtitle",