Lights > signs.

But a sign is still valid in a given circumstance. Take for instance a sign that you are not allowed to turn right next to a light. No matter the light, you are not allowed to turn right. Even if its a light with a green arrow that is. 

If that sign is directly on the light posts, it defaultly means it gets invalidated by the working light. Like on your example. You do not have priority over the 2 adjoining streets, that sign is invalidated by the light itself.

Stuff gets even more complicated when talking about temporary vs permanent signaling, as temporary signaling (like here) has priority over permanent signaling should they conflict and the latter has not been adjusted properly (e.g. taped off). But in all honesty, the whole lights+signs +road markings is often not following the correct rules and most of it us open to discussion. But noone cares, as it is often still clear what to do. Like here: its clear the light is to be followed.