#4996 broke File filters management
Removed package docblock
Merge pull request #5050 from Slamdunk/bugtest/filefilter

#4996 broke File filters management
[#5050] Fix for break in file input specifications

- File inputs inside fieldsets were causing issues.
- Issue was due to removal of a `$fieldset === $this` condition when
  determining whether or not to attach the input filter specification
  for a fieldset.
- Tests had an issue as well: the input specification needed to indicate
  the input type in order to ensure the correct `FileInput` type is
  created on the initial seeding of the input filter.
Merge branch 'hotfix/5050'

Close #5050