Don't send opening message if only open_since changed

This happens with HomeAssistant reboots.

src/bot.rs

@@ -58,6 +58,12 @@ pub enum OpenState {
     Closed,
 }
 
+impl OpenState {
+    pub fn is_open(&self) -> bool {
+        matches!(self, OpenState::Open { .. })
+    }
+}
+
 #[instrument(skip(api))]
 async fn get_open_state(api: &ItsApi) -> Result<OpenState> {
     let state = api
@@ -146,13 +152,16 @@ impl Bot {
     #[instrument(skip(self))]
     async fn update_open_state(&self) -> Result<OpenState> {
         let new_state = get_open_state(&self.api).await?;
-        if self
+
+        let is_open = new_state.is_open();
+        let was_open = self
             .open_state
             .lock()
             .unwrap()
-            .is_some_and(|old_state| old_state != new_state)
-        {
-            let message = if let OpenState::Open { .. } = new_state {
+            .as_ref()
+            .map(OpenState::is_open);
+        if was_open.is_some_and(|was_open| was_open != is_open) {
+            let message = if is_open {
                 "opening IT-Syndikat - Ohai!"
             } else {
                 "closing IT-Syndikat - nap time!"