Testing line tool

[0HyperCube]

Testcases:

• Works when the viewport is zoomed/panned/tilted (Add tests for Line tool with PTZ #2559)
• Works when the artboard has an offset, which this PR has currently broken so this also needs a fix
• Works when the artboard has a transform before it (Add Line tool tests for drawing within a transformed artboard #2572)
• Shift constrains to 15 degrees from the viewport (test when the viewport is rotated by 5 degrees) (Add tests for drawing lines with ctrl, shift, and alt #2490)
• Ctrl locks the angle when pressed (Add tests for drawing lines with ctrl, shift, and alt #2490)
• Alt drags from centre (test when combined with shift as well) (Add tests for drawing lines with ctrl, shift, and alt #2490)
• After drawing, selected layers only can have their endpoints dragged.

[prathmesh703]

@0HyperCube can you assign this issue to me?

[rahat2134]

@0HyperCube I want to complete this one, Can you assign me this?