In this situation, are you required to signal your intention to cross this dotted line with the direction-indicator?

In the situation shown, a white delivery van is parked in your lane. Passing it requires moving to the left side of the road and crossing the broken P-1 line. Performing this manoeuvre involves a lane change, so you are strictly required to signal it with the appropriate indicator. According to Art. 22 para. 5 of the Road Traffic Act, the driver is obliged to signal the intention to change lanes or direction in advance and clearly.