[shared_preferences] remove android no-op implementation

[cg021]

Description

Remove the Android directory in the shared_preferences's shared_preferences_web and shared_preferences_macos subdirectories. These are unused implementations and do not need to be included.

Related Issues

flutter/flutter#46304

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[blasten]

nit: typo

[cg021]

sorry- just fixed.

[blasten]

LGTM

[blasten]

It's deleting non-android folder now

[blasten]

It also needs to update bump the version of shared_preferences_web

[blasten]

LGTM

[kmfish]

FAILURE: Build failed with an exception.

• Where:
  Initialization script '/Users/username/sdk/flutter/packages/flutter_tools/gradle/aar_init_script.gradle' line: 15
• What went wrong:
  Android property not found.

It will cause build failed when the android directory is removed from the plugin.

[shenguojun]

when running command "flutter build aar", it will return "Android property not found." error. In the aar_init_script.gradle file , will check if project has property "android". Please don't delete android folder after correct the aar_init_script.gradle.