fix(color): Fix search for model specific audio files for switches.

[philmoz]

Another victim of the switch/ADC refactor PR.

Incorrect indexing of switches when looking for model specific audio file (e.g. SOUNDS/en/modelname folder).
Crashes simulator if model audio file exists.
Loads incorrect audio files on radio.

[raphaelcoeffic]

@philmoz it seems the old method had a lot of string copies (for each and every file) on top of re-fetching the model audio directory (which accesses the file system) for each and every try. The new method should be much faster. I added some unit-tests as well.

[pfeerick]

Did anyone try this on hardware after the last changes? As this isn't working for me on TX16S with a test file set that I just verified still works with 2.9.1. for fpv250, all three positions of SC should say something, as well as SF and SH. SL was a poorly named FM, but still works. Wondering if this is another ugly case of simu not behaving the same as hardware.

pr4162.zip

[philmoz]

Did anyone try this on hardware after the last changes?

Confirmed - works in simulator, does not work on TX16S.

[philmoz]

Should work now.

[pfeerick]

Yup, that fixed it! :)