Reader scroll area fix (#1257)

* Changes to make the pagination area scrollable (not working, debug code for Robbie)

* Adjusted the html to be easier to understand and more streamlined

* Fixed inability to scroll in manga reader over pagination areas for everything but the bottom bar

* Book reader now allows you to scroll over pagination area

API/Controllers/ReaderController.cs

@@ -116,6 +116,7 @@ namespace API.Controllers
         [HttpGet("chapter-info")]
         public async Task<ActionResult<ChapterInfoDto>> GetChapterInfo(int chapterId)
         {
+            if (chapterId <= 0) return null; // This can happen occasionally from UI, we should just ignore
             var chapter = await _cacheService.Ensure(chapterId);
             if (chapter == null) return BadRequest("Could not find Chapter");