chore: Remove legacy UI for telemetry type

[mha1]

Fixes #3776

Summary of changes:

• remove legacy UI for telemetry type
• CPN and b&w radios, was already deleted in color LCD UI

[raphaelcoeffic]

@mha1 if I understand this well, this is basically the second phase of #3352, right? Basically in the same "group of features" as #3780.

[mha1]

@raphaelcoeffic @pfeerick correct, this PR gets rid of the old zombie FrSky implementation which only made it half way into EdgeTX (b&W only), caused Companion to crash and created problems for a few users migrating from OpenTX on color radios. The good thing is it was hardly used anyways.

#3352 can serve as a template how to do it right in #3780's spirit.

Peter and I discussed the removal and are aware we might cause some (most likely only a handful) users a headache. The remedy would be to discuss the specific use case and extend the required module's capability as shown in #3352. The way the current old FrSky focused implementation handles things is incomplete and not worth keeping alive.

[raphaelcoeffic]

Thx @mha1 this is real documentation for the posterity!

[pfeerick]

From what I can tell, this is as expected. X9D+2019 doesn't have any issues in the telemetry screen as a consequence of this PR. I can't test the Companion side changes atm as it seems PPM is missing from the external module list atm (not related to this PR) but they look ok.