Slime's on bedrock edition will not spawn in light levels higher than 7. This breaks slime farms (which already get extremely low rates due to bad slime spawn rates) and is not in parity with java edition, where slime's can spawn in any light level.

To test this:
Get a super flat. Set to night, make it a full moon, and then set up a repeating command block with /kill @e[type=!slime]. The command will make so you can actually see slime's spawning. After you know they can spawn in an area, fill the surface of that area with torches or other light sources. And no slimes will spawn there. Lights need to be spaced 5 blocks gap apart to make everything 8 or above.

Tested this in slime chunks, and swamps. Nothing.