Clean up library download chapters logic

We can probably clean up the same logic in the manga controller at some point too, but that stuff's messy.
Also fixes the spacing issue that the new icon introduced.

(cherry picked from commit 33e90d6449)

# Conflicts:
#	app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt

app/src/main/java/eu/kanade/presentation/components/MangaBottomActionMenu.kt

@@ -9,7 +9,6 @@ import androidx.compose.animation.shrinkVertically
 import androidx.compose.foundation.combinedClickable
 import androidx.compose.foundation.interaction.MutableInteractionSource
 import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.RowScope
@@ -179,6 +178,7 @@ private fun RowScope.Button(
     toConfirm: Boolean,
     onLongClick: () -> Unit,
     onClick: () -> Unit,
+    content: (@Composable () -> Unit)? = null,
 ) {
     val animatedWeight by animateFloatAsState(if (toConfirm) 2f else 1f)
     Column(
@@ -210,6 +210,7 @@ private fun RowScope.Button(
                 style = MaterialTheme.typography.labelSmall,
             )
         }
+        content?.invoke()
     }
 }
 
@@ -272,15 +273,14 @@ fun LibraryBottomActionMenu(
                     )
                 }
                 if (onDownloadClicked != null) {
-                    Box {
-                        var downloadExpanded by remember { mutableStateOf(false) }
-                        this@Row.Button(
-                            title = stringResource(R.string.action_download),
-                            icon = Icons.Outlined.Download,
-                            toConfirm = confirm[3],
-                            onLongClick = { onLongClickItem(3) },
-                            onClick = { downloadExpanded = !downloadExpanded },
-                        )
+                    var downloadExpanded by remember { mutableStateOf(false) }
+                    Button(
+                        title = stringResource(R.string.action_download),
+                        icon = Icons.Outlined.Download,
+                        toConfirm = confirm[3],
+                        onLongClick = { onLongClickItem(3) },
+                        onClick = { downloadExpanded = !downloadExpanded },
+                    ) {
                         val onDismissRequest = { downloadExpanded = false }
                         DownloadDropdownMenu(
                             expanded = downloadExpanded,

app/src/main/java/eu/kanade/presentation/library/components/LibraryComfortableGrid.kt

@@ -72,7 +72,7 @@ fun LibraryComfortableGrid(
                     )
                 },
                 // SY -->
-                buttonBottom = if (showStartReadingButton) {
+                buttonBottom = if (showStartReadingButton && libraryItem.unreadCount > 0) {
                     { StartReadingButton(onOpenReader = { onOpenReader(libraryItem.libraryManga) }) }
                 } else {
                     null

app/src/main/java/eu/kanade/presentation/library/components/LibraryCompactGrid.kt

@@ -73,12 +73,12 @@ fun LibraryCompactGrid(
                     )
                 },
                 // SY -->
-                buttonTop = if (showStartReadingButton && showTitle) {
+                buttonTop = if (showStartReadingButton && showTitle && libraryItem.unreadCount > 0) {
                     { StartReadingButton(onOpenReader = { onOpenReader(libraryItem.libraryManga) }) }
                 } else {
                     null
                 },
-                buttonBottom = if (showStartReadingButton && !showTitle) {
+                buttonBottom = if (showStartReadingButton && !showTitle && libraryItem.unreadCount > 0) {
                     { StartReadingButton(onOpenReader = { onOpenReader(libraryItem.libraryManga) }) }
                 } else {
                     null