fix(Android): replace deprecated EXIF ISO tag

[CaiJingLong]

Related Issue

Closes #402

Problem

Android's ExifKeeper referenced the deprecated ExifInterface.TAG_ISO_SPEED_RATINGS constant, so Java compilation emitted a deprecation note on every consumer build. The issue reproduction and maintainer follow-up confirmed that AndroidX 1.4.2 maps the legacy name to TAG_PHOTOGRAPHIC_SENSITIVITY for the same underlying EXIF tag.

Changes

• Replace TAG_ISO_SPEED_RATINGS with TAG_PHOTOGRAPHIC_SENSITIVITY in the EXIF attribute copy list.
• Keep the runtime EXIF copy behavior unchanged while removing the deprecated Java API reference.

Verification

• RED: compiled the unmodified full ExifKeeper.java with AndroidX 1.4.2 using javac -Xlint:deprecation -Werror; it failed only on TAG_ISO_SPEED_RATINGS.
• GREEN: reran the identical command after the change; it completed with no diagnostics.
• dart run melos exec -- "dart format . -o none --set-exit-if-changed" - passed, 0 files changed.
• dart run melos run analyze - passed for all 7 packages.
• Android :flutter_image_compress_common:compileDebugJavaWithJavac --rerun-tasks - passed.
• Android assembleDebug - passed, 178 tasks completed and app-debug.apk produced.
• melos run test is not runnable on the current main: all 7 packages report that their test directory is absent. The repository CI does not invoke this script; the affected compile path is covered directly above.

Risk

• Low. The change is limited to one compile-time constant in ExifKeeper; AndroidX preserves compatibility for the same EXIF field, so image metadata behavior is unchanged.

Standards

• Followed CONTRIBUTING.md for the main target and Conventional Commit format.
• Followed .github/workflows/runnable.yml for format, analysis, and Android build verification.
• The repository has no PR template or agent-specific instruction file, so the general PR structure was used.