end session correctly for firefox

apps/remix-ide-e2e/src/tests/file_explorer_multiselect.test.ts

@@ -26,7 +26,11 @@ module.exports = {
   },
   'Should drag and drop multiple files in file explorer to tests folder #group1': function (browser: NightwatchBrowser) {
     const selectedElements = []
-    if (browser.browserName.indexOf('firefox') > -1) return
+    if (browser.options.desiredCapabilities.browserName === 'firefox') {
+      console.log('Skipping test for Firefox')
+      browser.end()
+      return
+    }
     browser
       .click({ selector: '//*[@data-id="treeViewUltreeViewMenu"]', locateStrategy: 'xpath' })
       .click({ selector: '//*[@data-id="treeViewLitreeViewItemcontracts/1_Storage.sol"]', locateStrategy: 'xpath' })