SX126x/8x: Also use PREAMBLE_DETECTED IRQ flag for actively receiving check (#2349)

* Use startReceive() instead of startReceiveDutyCycleAuto()

* Add preamble detected IRQ

* Escape from 'freeze' state when packet should have been received

* Use RADIOLIB_GODMODE for access to clearIrqStatus

* SX126x: Better handling of false preamble detections

* SX128x: Add preamble IRQ and false detection handling to active receiving check

* Remove unnecessary function declaration

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Co-authored-by: Ben Meadors <benmmeadors@gmail.com>

src/mesh/SX126xInterface.h

@@ -68,4 +68,5 @@ template <class T> class SX126xInterface : public RadioLibInterface
     virtual void setStandby() override;
 
   private:
+    uint32_t activeReceiveStart = 0;
 };