NULL pointer deferencement when exiting the app

### Describe the bug.

A NULL pointer dereference occurs when quickly entering receive mode and exiting the app by double-pressing the back button before the Grove LoRa-E5 module has time to initialize.

### Reproduction

1. Launch the app
2. Enter Receive Mode
3. Quickly press the Back button twice

### Target

_No response_

### Logs

```Text

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### Anything else?

_No response_