Pr aero battery initialization hotfix

[MaEtUgR]

On the Intel Aero and probably also other specific platforms the first measured voltage values despite connected battery are unuasable. The solution here is to start filtering and determining warning only after a measurement above 2.1V was received. This condition was anyways used before to determine if the battery status report gets filled at all.

I bench tested this on an Intel Aero. Can someone else please also confirm?

fixes #8930

[ChristophTobler]

@santiago3dr Can you please also test this on the platforms that you had issues with battery estimation?

[LorenzMeier]

@MaEtUgR Please assign @PX4/testflights as reviewer for things that need on-HW testing. @PX4/testflights please make sure this doesn't break any other config that you fly. Please test different vehicles.

[Avysuarez]

Flight with pixhawk 1- V2. No issues.
https://review.px4.io/plot_app?log=ef52ad42-e479-4f9c-a79d-3e1fcffeaff5

Flight with pixhawk Pro - V4pro. No issues.
https://review.px4.io/plot_app?log=5ab4353a-7cb6-419d-9883-312da3694415

[r0gelion]

I noticed a recurrent warning message in the log from Pixhawk 1 - V2

What does this mean?

Regards

[santiago3dr]

pixracer (v4):
https://logs.px4.io/plot_app?log=6858c85e-16cb-4960-b258-c24f393c87ed

snapdragon (eagle):
https://logs.px4.io/plot_app?log=f0680eb8-ed03-4094-a7b5-db58e4fd9b14

all features working as expected; no notable difference from master

aerotenna (OcPoc):
https://logs.px4.io/plot_app?log=90f9c02b-9304-4a54-bf50-a1a83d80c850

looks to have resolved issue #8932

[dannyfpv]

pixhawk mini v3.- the battery sensor worked very well
https://logs.px4.io/plot_app?log=7d2cf902-9ac9-4818-a57f-32a2085fa572
https://logs.px4.io/plot_app?log=95023377-1218-47a6-b753-a246d659bf33

[r0gelion]

The PR performed well on other platforms than the aero, we couldn't test it in the aero due to connection issues, but @MaEtUgR tested it (bench testing).