SpecialContributions: Fix whitespace in tagfilter

SpecialContributions: Fix whitespace in tagfilter

Removing the first element of an array, and using it as a label, doesn't make
much sense, if the array will be imploded using a whitespace to add a whitespace
between both array parts.

Instead of writing:
Tag filter:<input>

this will result in the expected output:
Tag filter: <input>

Change-Id: Ifc9de7cc6ab380fcff435fcd0410963e72ef6203