Fix brightness icon when swiping to close flashlight

[serosi]

module: DisplayApp.cpp

Fixed #1751: when swiping to close flashlight, the brightness icon now resets to the actual brightness instead of the flashlight's brightness.

[github-actions[bot]]

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[JF002]

The original issue was fixed by a refactoring of the brightness introduced by the always on feature #1869. Closing this one.

Thanks for your contribution @serosi :1st_place_medal: