Add SlotMeta unit test for connected at slot zero (#29025)

ledger/src/blockstore_meta.rs

@@ -421,6 +421,12 @@ mod test {
         rand::{seq::SliceRandom, thread_rng},
     };
 
+    #[test]
+    fn test_slot_meta_slot_zero_connected() {
+        let meta = SlotMeta::new(0 /* slot */, None /* parent */);
+        assert!(meta.is_connected());
+    }
+
     #[test]
     fn test_erasure_meta_status() {
         use ErasureMetaStatus::*;