Fix LED light pipe fit

[manuelkasper]

The polycarbonate light pipe (Bivar SLP3-150-100-F) used for the RGB LED in rev2 has a protrusion for the "lens" that does not fit through the hole in the back of the KX2's case. The light pipe is too high above the PCB.

Ideas:

• Find another light pipe that fits
• Go back to right angle LED from rev1 and stick a simple flat piece of semi-opaque plastic to the inside of the hole
• Use a THT LED
  • Elecraft seems to be using a 3 mm THT LED on the KXIBC2, but RGB LEDs only seem to come in 5 mm versions, which would stick out quite far
• 3D print something? (does not conduct light so well...)

[manuelkasper]

Found this SMD part from Dialight that could fit: https://www.dialightsignalsandcomponents.com/591-prism-smd-3mm-rnd-tricolor-r-g-b-13-reel/

However, it's quite expensive ($2.5 at qty. 100)