[camera_android] Convert Dart to native calls to use Pigeon (flutter#7874)

Add structured types and convert implementations to use typesafe method
calls for platform methods from Dart to native side.

Android analog of flutter/packages#6601

Part of flutter#117905

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[test-exempt]:
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Author: yaakovschectman

packages/camera/camera_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.10.9+15
+
+* Converts Dart to native platform calls to Pigeon.
+
 ## 0.10.9+14
 
 * Converts native to Dart platform calls to Pigeon.