Absolutely, yes.
The minimum power requirement for the 1050Ti is 300W, you don't have as near as that with that PSU.
Putting a GPU in a rig without proper a power supply could lead to very dangerous situations for you rig as a whole.
It will be powered by the MOBO yes, but it will still draw as much energy as it would from a PSU. Those pre-made PCs are made to work what they have within them, any change on that may lead to have to change other things as well.
If you're looking for a cheap solution for this, try to get yourself a CX450M or a SeaSonic S12 520W.