fix(cy): avoid double upload to prevent lock error

`isolateTest` in `beforeEach` already uploads the file.

Uploading it again in the `no actual conflict - just reload` case

sometimes led to 423 - Locked responses.

Use `cy.createTestDir()` instead and upload only once.

Signed-off-by: Max <max@nextcloud.com>

[skip ci]

cypress/e2e/conflict.spec.js

@@ -1,7 +1,7 @@
 /**
- * @copyright Copyright (c) 2019 John Molakvoæ <skjnldsv@protonmail.com>
+ * @copyright Copyright (c) 2022 Nextcloud GmbH and Nextcloud contributors
  *
- * @author John Molakvoæ <skjnldsv@protonmail.com>
+ * @author Max <max@nextcloud.com>
  *
  * @license AGPL-3.0-or-later
  *
@@ -20,16 +20,15 @@
  *
  */
 
-import { initUserAndFiles, randUser } from '../utils/index.js'
-
-const user = randUser()
+import { randUser } from '../utils/index.js'
 
 const variants = [
 	{ fixture: 'lines.txt', mime: 'text/plain' },
 	{ fixture: 'test.md', mime: 'text/markdown' },
 ]
 
 variants.forEach(function({ fixture, mime }) {
+	const user = randUser()
 	const fileName = fixture
 	describe(`${mime} (${fileName})`, function() {
 		const getWrapper = () => cy.get('.text-editor__wrapper.has-conflicts')