remove null value

lesson learnt
never use any Kaggle datasets without checking for null values

phishing_url_train.csv

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:107d6a25a286f02babbbfe3b48e5bc72a9926391b6ae4dead4a13ba2ff0338fe
-size 145629352
+oid sha256:f0a78249a80a71942ddbb18b39bc9405f67d5d7d0944c1c18c9e0d8cca638573
+size 145629294