feat: non inverted SBUS trainer support on serial inputs on H5/H7

[3djc]

This PR does 3 things:

• sanitize translations: "SBUS trainer" was used when actually inverted SBUS was required
• allow H5/H7 radio to choose either mode, so that regular SBUS or inverted can both be use for trainer on serial ports
• provide ETX_Pol_Inverted support to simple uarts (ie not "ports")

@elecpower could you take care of the companion side ?

[elecpower]

@elecpower could you take care of the companion side ?

Yes

[elecpower]

@3djc when #7136 is merged into 3.0 any cpu related features will required separate PRs for earlier versions, so what versions are you planning to add this to?

[3djc]

Whatever makes your life easier. If 3.0 only, so be it

[pfeerick]

It would be better though as 2.12 also though (I.e. 2.12.1 material), given that is intended as the h7 stable branch. But whatever works.

[elecpower]

I'll do one for each with the 3.0 post CPU merge