Tags consisting of space only can be added to search field

Tags consisting of space only can be added to search field. In additional, tags, ending with space and the same tags witout spaces count as different tags, for example 'tag' and 'tag ' and 'tag '.

Test scenario: Space only consists tag added
Steps to reproduce:

1. Open Antarcticle main page
2. Input space, comma
   Actual reault: Tag added to search field
   Expected result: tag was not added to search field

Test scenario: tag ending with space
Steps to reproduce:

1. Open  Antarcticle main page
2. Input tag , comma.
3. Input tha same tag, space, comma.
   Actual reault: Tag added to search field 
   Expected result: tag was not added to search field

Both scenarios reproduced on prod instance
Tag may consist of more than one space