fix(android): remove WRITE_EXTERNAL_PERMISSION

[breautek]

Platforms affected

Android

Motivation and Context

This was intended to be part of #909
But I forgot to sync the change to plugin.xml

Description

Removes the automatic declaration for WRITE_EXTERNAL_STORAGE, letting end users add it to their config.xml if they need it depending on their use cases.

Testing

YOLO paramedic (j.k. I've done lots of testing with and without the declaration)

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[erisu]

LGTM

The removal is expected, as the README already instructs app developers to add this to their own config.xml if they support Android SDK 28 or lower, following a permission opt-in strategy.