Adds `setJpegImageQuality(int quality)` (1–100) to the app-facing `camera` package, forwarding to the platform interface method.

This PR is now scoped down to `camera` only. The platform interface and implementations already landed and published separately:

| Package | Version | Landed in |
|---------|---------|-----------|
| `camera_platform_interface` | 2.13.0 | #11155 (split out) |
| `camera_platform_interface` | 2.13.1 | #12123 — default implementation made a no-op |
| `camera_android_camerax` | 0.7.4 | #11616 |
| `camera_avfoundation` | 0.10.2 | #11616 |

### This PR

| Package | Version |
|---------|---------|
| `camera` | 0.12.0+2 → 0.12.1 |

* Adds `CameraController.setJpegImageQuality`, with 1–100 range validation and `CameraException` translation.
* Bumps constraints to the published versions that implement it: `camera_platform_interface: ^2.13.1`, `camera_android_camerax: ^0.7.4`, `camera_avfoundation: ^0.10.2`. No `dependency_overrides`.
* Per the review discussion, the platform interface default is a no-op rather than an `UnimplementedError`, so calling this is always safe. The dartdoc says the setting is best-effort and links to https://github.com/flutter/flutter/issues/191790 for the current state of platform support (web and Windows are not implemented yet).

Fixes https://github.com/flutter/flutter/issues/183229

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