[Android Deployment Docs] Clean up outdated sections, legacy embedder references, and duplicate command

[lamek]

The Build and release an Android app page contains several stale sections and minor errors that need cleanup:

1. Legacy Multidex section: Mentions targeting API < 20, which Flutter no longer supports, and contains outdated CLI/IDE screenshots.
2. Outdated Android Studio screenshots: The Build Variants and Gradle module screenshots show the legacy Android Studio UI from several versions ago.
3. Garbled command in FAQ: The command in the FAQ has duplicated arguments: apkanalyzer files list --files-only <SOME-APK> files list --files-only <SOME-APK>.
4. v1 Embedder FAQ item: Recommends checking for flutterEmbedding="1", which is obsolete since v1 embedders were removed in Flutter 3.22.
5. Java 9 reference: Notes that -storetype JKS is required for "Java 9+", whereas Java 17/21 is the standard for modern Android development.
6. Third-party tools: Mentions third-party community tools ("Flutter Shark" / "Flutter Hunt") in the FAQ that should be reviewed for currency.