Fix: Remove changes to the Interner

- Remove stale methods `contains` and `get_interned` from `Interner` in favor of the changes introduced by Qiskit#13752.

crates/circuit/src/interner.rs

@@ -391,25 +391,6 @@ where
             _type: PhantomData,
         }
     }
-
-    /// Checks whether an item is already packed in the interner
-    pub fn contains(&self, value: &T) -> bool
-    where
-        T: Hash + Eq,
-    {
-        self.0.contains(value)
-    }
-
-    /// Retrieves interner index of anitem if it exists
-    pub fn get_interned(&self, value: &T) -> Option<Interned<T>>
-    where
-        T: Hash + Eq,
-    {
-        self.0.get_index_of(value).map(|index| Interned {
-            index: index as u32,
-            _type: PhantomData,
-        })
-    }
 }
 
 impl<T> Interner<T>