fix(android): add missing import androidx.core.app.ActivityCompat

[erisu]

Motivation and Context

Resolve "PushPlugin.kt:616:13 Unresolved reference: ActivityCompat"

Description

Added missing import for androidx.core.app.ActivityCompat

Related Issue

n/a

Reported in comment: #325 (comment)

How Has This Been Tested?

Created blank android project, added plugin, and run build.

• confirmed issue without PR changes
• confirmed that the issue has been was resolved with PR changes

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.