Add phan seccheck to composer and remove deprecated module

Seccheck is currently being executed as non-voting, but it always
succeeds because AbuseFilter is not requiring it in composer. Instead,
let's add it: tests will start to fail, but we'll be able to see how
things are going with it. As a bonus, remove the mediawiki.api.parse
module, which is deprecated in 1.32 and replaced by mediawiki.api
(already loaded).

Change-Id: I094a8af4f97c03f8b538ede00420b123de25138a

composer.json

@@ -25,5 +25,8 @@
 			"phpcs -p -s",
 			"minus-x check ."
 		]
+	},
+	"extra": {
+		"phan-taint-check-plugin": "1.2.0"
 	}
 }

extension.json

@@ -167,7 +167,6 @@
 			"dependencies": [
 				"mediawiki.util",
 				"mediawiki.api",
-				"mediawiki.api.parse",
 				"jquery.textSelection",
 				"jquery.spinner"
 			]