File->getDestination fails without extension

[MGatner]

Describe the bug
Calling $file->move() and providing a new filename without an extension causes a failed array reference because pathinfo() does not have an extension key in the resulting array.

CodeIgniter 4 version
Latest develop

Affected module(s)
File Class, HTTPFile Class

Context

• OS: Linux
• Web server: Apache
• PHP version: 7.2

[MGatner]

CRITICAL - 2019-07-24 15:38:09 --> Undefined index: extension
#0 ./vendor/codeigniter4/codeigniter4/system/Files/File.php(223): CodeIgniter\Debug\Exceptions->errorHandler(8, 'Undefined index...', '/srv/web/...', 223, Array)
#1 ./vendor/codeigniter4/codeigniter4/system/HTTP/Files/UploadedFile.php(176): CodeIgniter\Files\File->getDestination('/srv/web/...')
#2 ./app/Controllers/Files.php(46): CodeIgniter\HTTP\Files\UploadedFile->move('/srv/web/...', 'noext')
#3 ./vendor/codeigniter4/codeigniter4/system/CodeIgniter.php(838): App\Controllers\Files->upload()
#4 ./vendor/codeigniter4/codeigniter4/system/CodeIgniter.php(335): CodeIgniter\CodeIgniter->runController(Object(App\Controllers\Files))
#5 ./vendor/codeigniter4/codeigniter4/system/CodeIgniter.php(245): CodeIgniter\CodeIgniter->handleRequest(NULL, Object(Config\Cache), false)
#6 ./public/index.php(45): CodeIgniter\CodeIgniter->run()