PR: Fix has_module_settings flag inconsistency in channel updates

[blahman5000]

Summary

Fixes a bug where channels could be created/configured with populated module_settings (e.g., position_precision, is_muted) but leave has_module_settings=false. This caused position and mute state to be ignored by downstream code.

One consequence of this is that manual position requests on a channel configured for full-precision location would sometimes (depending on how the channel was created) return Null Island.

Root Cause

setChannel() was accepting incoming meshtastic_Channel objects without validating the has_module_settings flag. When a channel from an external source (phone API, etc.) carried module_settings data but didn't set the flag, those settings would overwrite the stored channel while appearing disabled.

Solution

Added normalization logic to setChannel() and fixupChannel():
If any module_settings fields are non-zero (position_precision or is_muted), ensure has_module_settings=true.

Testing

Idempotent: calling setChannel() multiple times on the same object has no side effects. fixupChannel() applies the same logic to stored channels at boot and on config changes (via onConfigChanged()).

Impact

Risk: Low — purely additive validation; no behavior changes for well-formed channels.

🤝 Attestations

• I have tested that my proposed changes behave as described.
• I have tested that my proposed changes do not cause any obvious regressions on the following devices:
  • Heltec (Lora32) V3
  • LilyGo T-Deck
  • LilyGo T-Beam
  • RAK WisBlock 4631
  • Seeed Studio T-1000E tracker card
  • Heltec (Lora32) V4
  • Wio Tracker L1

[CLAassistant]

All committers have signed the CLA.

[github-actions]

@blahman5000, Welcome to Meshtastic!

Thanks for opening your first pull request. We really appreciate it.

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