Fix ItemGrid backdrop when alpha is active and prevent loading background twice on first load

[cewert]

I added a bunch of debugging and since it will all be removed when prod is built I didn't see a reason to remove it 🤷‍♂️ It makes the log pretty chatty though. I used m.log.debug for everything but I'm open to suggestions on how to do the logging.

This PR resets the ItemGrid backdrop to nothing when using the alpha menu. A blank uri string didn't work with the animation so I'm using a 1px image hardcoded to our apps bgcolor. This helps see the alpha menu letters as well as preventing the weird situation of the backdrop sticking around when a new letter is selected.

Preventing the double background loading bug was a one liner and didn't deserve the effort to make another PR :) the double fire did cause the queue to contain the uri of the item focused on first load so I believe it did cause a bug where the wrong poster would load on second movement at times but it was hard to reproduce.
if itemInt = -1 or focusedRow = -1. focusedRow is -1 but causes onItemFocused() to fire when the page is first loaded,

Changes

• add a bunch of logging
• create 1px image same color as app bgcolor
• observe m.top.alphaActive and animate to 1px image whenever true

Note for testing

Movies use their own view which didn't seem to need these type of changes and same for music. All other libraries use the item grid. I mostly tested with a collection and tv show library

[jellyfin-bot]

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[jellyfin-bot]

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