Sequencer - Pressing Add Key on Rotation-Yaw increases the key value exponentially

Not a critical bug but add unnecessary workload since the user found himself constantly checking Yaw values.

1. Create a level sequence
2. Add an actor
3. Set Rotation - Yaw to 182.0 and press add key
4. Press add key repeatedly

Result:

Key value increase by 360 * pow(2, n-1) every time you press it. Happens when you add key at other time frames too.

Expected:

Key value stays at 182.0