fix: return unique subdivision IDs when "All" selected

Co-authored-by: aider (deepseek/deepseek-chat) <aider@aider.chat>

app.R

@@ -361,13 +361,13 @@ server <- function(input, output, session) {
   
   filteredSbdvn <- reactive({
     if (is.null(input$sub_name) || input$sub_name == "All") {
-      return(sbdvn$max_sub_id)
+      return(unique(sbdvn$max_sub_id))
     } else {
       return(
         sbdvn %>% 
         filter(sub_name == input$sub_name) %>% 
         pull(max_sub_id)
-        )
+      )
     }
   })