Fix logged error if file ID is not available

[MorrisJobke]

fixes errors like this:

"url":"/apps/gallery/preview/426429?width=3400&height=3400&c=594c37c83d999&requesttoken=VY8nKK5eeu3W6uVKtFvD+YSnXVfoXdas+mQvmFgXZGU=:YsZFTOgXCoOk3td/wQiVivTKFTOpC5fKmSNswDRQNFE=",
"message":"Undefined offset: 0 at /var/www/nextcloud/apps/gallery/lib/Environment/Environment.php#360",

and

"url":"/apps/gallery/preview/426429?width=3400&height=3400&c=594c37c83d999&requesttoken=VY8nKK5eeu3W6uVKtFvD+YSnXVfoXdas+mQvmFgXZGU=:YsZFTOgXCoOk3td/wQiVivTKFTOpC5fKmSNswDRQNFE=",
"message":"ExceptionCould not locate node linked to ID: 426429",

to only log the last error and not both.

[MorrisJobke]

See https://3v4l.org/0cXQA for behaviour. no matter if the element is there or not it will evaluate to true then.

[codecov]

Codecov Report

Merging #288 into master will not change coverage.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master     #288   +/-   ##
=========================================
  Coverage     81.93%   81.93%           
  Complexity      334      334           
=========================================
  Files            38       38           
  Lines          1284     1284           
=========================================
  Hits           1052     1052           
  Misses          232      232

Impacted Files	Coverage Δ	Complexity Δ
lib/Environment/Environment.php	95.55% <100%> (ø)	28 <0> (ø)	⬇️

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