chore(eslint): remove deprecated eslint-env

These comments did not work anymore and were replaced by relevant
sections in eslint.config.mjs

Signed-off-by: Philip Molares <philip.molares@udo.edu>

test/csp.js

@@ -1,4 +1,3 @@
-/* eslint-env node, mocha */
 'use strict'
 
 const assert = require('assert')

test/letter-avatars.js

@@ -1,5 +1,3 @@
-/* eslint-env node, mocha */
-
 'use strict'
 
 const assert = require('assert')

test/user.js

@@ -1,5 +1,3 @@
-/* eslint-env node, mocha */
-
 'use strict'
 
 const assert = require('assert')