[BUGFIX] Correctly check decoded content

On publishing a new extension version, the content of each
file is checked against the calculated MD5 checksum. If the
file content is however an empty string, this check previously
failed. Therefore, the `$decodedContent` is now strictly
checked for `false`.
10 jobs for 504-error-md5-does-not-match-for-file-classes-on-version-upload in 6 minutes and 43 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Maintenance
manual Get dump for local environment #29899
allowed to fail manual
 
  Test
passed test:composer #29902

00:01:46

passed test:mutation #29904

00:03:41

passed test:php #29901

00:00:18

passed test:typoscript #29900

00:00:16

passed test:unit #29903

00:03:21

13.91%
 
  Build
passed build #29905

00:00:39

 
  Layout
passed layout #29906

00:01:27

 
  Badges
passed Create Badge #29907

00:00:48

passed mutation:badge #29908

00:00:51