build: Remove redundant eslint globs from Gruntfile.js

These ignores are already in package.json. Placing these here was
making `npm test` wait 10-20 seconds doing nothing waiting for Grunt
to synchronously recursively glob and expand an array of every file
in the current working directory (incl node_modules, and vendor) and
then once more for node_modules and vendor, and then to filter one
out from the other. And all before eslint even starts.

Instead, give '.' to eslint as we do in some other repos already,
and let it iterate on its own, skipping sub directories as it goes
based on package.json/eslintIgnore.

This follows-up 445087e5f, which did this once before,
and be400fe75 which unintentionally brought the Gruntfile part
back while leading the other part behind.

Change-Id: If637f2a696326778f25ea208224f5ac101f8c64a

Gruntfile.js

@@ -14,10 +14,7 @@ module.exports = function ( grunt ) {
 				fix: grunt.option( 'fix' )
 			},
 			all: [
-				'**/*.{js,json}',
-				'!lib/**',
-				'!resources/js/ext.uls.webfonts.repository.js',
-				'!{vendor,node_modules}/**'
+				'.'
 			]
 		},
 		stylelint: {