graphdb: pass context to PruneTip

graph/db/kv_store.go

@@ -1887,7 +1887,7 @@ func (c *KVStore) DisconnectBlockAtHeight(height uint32) (
 // used to prune channels in the graph. Knowing the "prune tip" allows callers
 // to tell if the graph is currently in sync with the current best known UTXO
 // state.
-func (c *KVStore) PruneTip() (*chainhash.Hash, uint32, error) {
+func (c *KVStore) PruneTip(_ context.Context) (*chainhash.Hash, uint32, error) {
 	var (
 		tipHash   chainhash.Hash
 		tipHeight uint32