Fix ui_step for crt-consumer.fx

[user18081972]

For crt-consumer.fx, the ui_step was set to 0, for Scanlines bright/dark.
This PR changes it to 0.05 (same as in Retroarch).

Click for boring and obvious explanation as to why UI_Step=0 is bad

When ui_step = 0, Changing the values for Scanlines bright/dark through the UI, forces the value of the shader parameter to the minimum (0.5), and makes it impossible to change it to anything else. This forces the user to remove and re-add the shader, and still being unable to change the values for Scanlines bright/dark to the desired value.

Shameless begging: Stenzek please add the Duckstation shader system to PCSX2 🥺

[stenzek]

Thanks!

Shameless begging: Stenzek please add the Duckstation shader system to PCSX2 🥺

FYI, I'm no longer associated with PCSX2 (haven't properly been since the start of the year), so that won't be happening, sorry.