EVBox Elvi: disable buggy *.Offered and SoC measurands

[andig]

Summary

• The Elvi charger reports nonsensical values for Current.Offered, Power.Offered and SoC, causing repeating "current mismatch (got 90A, expected 6A)" warnings and "charger out of sync" errors.
• Remove these measurands from the desired OCPP set via metervalues: -Current.Offered,Power.Offered,SoC, matching the existing pattern used for the Wallbox FW5 template.
• Drop the meter: false render branch (which itself only configured the buggy Current.Offered) and mark the now-unused meter param deprecated.

Closes #29588 (per @premultiply's suggestion in #29588 (comment)).

Test plan

• Run an Elvi with default config and confirm no more "current mismatch" / "out of sync" warnings.

[sourcery-ai]

Hey - I've reviewed your changes and they look great!

---

Sourcery is free for open source - if you like our reviews please consider sharing them ✨

• X
• Mastodon
• LinkedIn
• Facebook

_{Help me be more useful! Please click 👍 or 👎 on each comment and I'll use the feedback to improve your reviews.}