[camera_android] Reset AE and AF triggers to idle after capture (#11330)

## Issue
App freezes during focus/flash sequence in low light.
On high-end camera devices, focusing takes longer in dark environments. Repeatedly requesting focus while using the flash can cause the CaptureRequest to hang. 

> The [issues](https://github.com/flutter/flutter/issues/97501) has been resolved.
> I reproduced the same behavior on a different device (not an Xperia).

This log has been captured on my Xperia device.
```
D/CameraCaptureCallback(12647): CameraCaptureCallback | state: STATE_CAPTURING | afState: 1 | aeState: 5
D/CameraCaptureCallback(12647): CameraCaptureCallback | state: STATE_CAPTURING | afState: 1 | aeState: 5
D/CameraCaptureCallback(12647): CameraCaptureCallback | state: STATE_CAPTURING | afState: 5 | aeState: 4
D/CameraCaptureCallback(12647): CameraCaptureCallback | state: STATE_CAPTURING | afState: 5 | aeState: 4
D/CameraCaptureCallback(12647): CameraCaptureCallback | state: STATE_CAPTURING | afState: 1 | aeState: 4
I/Camera  (12647): refreshPreviewCaptureSession
```

## Root Cause
Camera2 trigger controls are driven by one-shot states (START), but they are not always reset to IDLE once the sequence is complete. On certain devices (like the Xperia 1), this failure to reset can block subsequent capture requests.

## Fix
`runPrecaptureSequence():` 
Send an AE trigger START, then immediately follow with IDLE in the same execution path.

`lockAutoFocus():` 
Send an AF trigger START, then reset to IDLE after the preview request is captured.

## Results
AE/AF triggers are now consistently returned to the IDLE state.
The freeze during capture after using the flash on Xperia 1 has been resolved.
Camera trigger sequences are now stable across various device models.

------
### By the way, 
I believe [CameraX](https://pub.dev/packages/camerax)  is the way to go for Android camera development. It's been the default since version 0.11.0.

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