Clean up UpdatesController

- Move loading state into scaffold (closes #7704)
- Move logic into presenter
- Make some composables private

app/src/main/java/eu/kanade/presentation/browse/ExtensionsScreen.kt

@@ -91,7 +91,7 @@ fun ExtensionScreen(
 }
 
 @Composable
-fun ExtensionContent(
+private fun ExtensionContent(
     state: ExtensionsState,
     onLongClickItem: (Extension) -> Unit,
     onClickItemCancel: (Extension) -> Unit,
@@ -201,7 +201,7 @@ fun ExtensionContent(
 }
 
 @Composable
-fun ExtensionItem(
+private fun ExtensionItem(
     modifier: Modifier = Modifier,
     item: ExtensionUiModel.Item,
     onClickItem: (Extension) -> Unit,
@@ -238,7 +238,7 @@ fun ExtensionItem(
 }
 
 @Composable
-fun ExtensionItemContent(
+private fun ExtensionItemContent(
     extension: Extension,
     modifier: Modifier = Modifier,
 ) {
@@ -294,7 +294,7 @@ fun ExtensionItemContent(
 }
 
 @Composable
-fun ExtensionItemActions(
+private fun ExtensionItemActions(
     extension: Extension,
     installStep: InstallStep,
     modifier: Modifier = Modifier,
@@ -348,7 +348,7 @@ fun ExtensionItemActions(
 }
 
 @Composable
-fun ExtensionHeader(
+private fun ExtensionHeader(
     @StringRes textRes: Int,
     modifier: Modifier = Modifier,
     action: @Composable RowScope.() -> Unit = {},
@@ -361,7 +361,7 @@ fun ExtensionHeader(
 }
 
 @Composable
-fun ExtensionHeader(
+private fun ExtensionHeader(
     text: String,
     modifier: Modifier = Modifier,
     action: @Composable RowScope.() -> Unit = {},
@@ -382,7 +382,7 @@ fun ExtensionHeader(
 }
 
 @Composable
-fun ExtensionTrustDialog(
+private fun ExtensionTrustDialog(
     onClickConfirm: () -> Unit,
     onClickDismiss: () -> Unit,
     onDismissRequest: () -> Unit,