[BUG] Filter's dataType gets the last filter value even if already has a valid value

[c3s4rfred]

Describe the bug
Because of a mutate bug, when a pipeline has more than one filter, the dataType can end with the value of the default filter's dataType. So, the default filter must check if has a dataType, if not then apply default.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'Data parsing'
2. Click on 'Syslog' pipeline
3. Add a new valid filter

Expected behavior
Final dataType must be the one of the new filter added

Environment

• UTMStack QA

Possible solution
Modify JSON, Syslog and generic filters