Clean up image permissions for Android

[hjiangsu]

Pull Request Description

This PR removes the following permissions from AndroidManifest:

• READ_EXTERNAL_STORAGE
• READ_MEDIA_IMAGES
• READ_MEDIA_VIDEO

The main reason for this is to comply with some Google Play Store requirements. Here is an article containing more information about this: https://support.google.com/googleplay/android-developer/answer/14115180

As a result, I've also updated the way permissions are requested when saving images in the image viewer. We no longer use permission_handler, but rather handle permissions through the gal package. Additionally, I've removed the device_info_plus dependency since it looks like it's no longer needed.

All in all, this reduces some of our permission logic, and cleans up some of our dependencies!

@micahmo I did some testing on Android emulators (specifically, API versions 35 and 29), so it should be working as expected. However, please let me know if you encounter any issues saving or uploading images!

Issue Being Fixed

Issue Number: N/A

Screenshots / Recordings

Checklist

• If a new package was added, did you ensure it uses an appropriate license and is actively maintained?
• Did you use localized strings (and added appropriate descriptions) where applicable?
• Did you add semanticLabels where applicable for accessibility?

[micahmo]

LGTM, I'll let you know if I run into any issues with these changes!