Fix null array index bug for PHP 7.4 (#2780)
Fix null array index bug for PHP 7.4 (#2780)

Fix https://github.com/FreshRSS/FreshRSS/issues/2775
Especially for PHP 7.4+ "Array-style access of non-arrays"
https://php.net/migration74.incompatible
aledeg/FreshRSS,FreshRSS/FreshRSS,Alkarex/FreshRSS,romibi/FreshRSS,marienfressinaud/FreshRSS,FreshRSS/FreshRSS,aledeg/FreshRSS,Alkarex/FreshRSS,FreshRSS/FreshRSS,romibi/FreshRSS,marienfressinaud/FreshRSS,FreshRSS/FreshRSS,romibi/FreshRSS,Alkarex/FreshRSS,aledeg/FreshRSS,aledeg/FreshRSS,romibi/FreshRSS,Alkarex/FreshRSS,marienfressinaud/FreshRSS,marienfressinaud/FreshRSS