feat: Added option to hide powerups from reward menu

[ChrisScr3ams]

Proposed changes

in the reward menu the options for power ups are now always displayed above all the channel point rewards. To make the menu cleaner an option to hide these power ups should be added.

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• Bugfix (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 not work as expected)
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Checklist

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Further comments

A slider option to hide the power ups from the reward menu was added to the settings under Site Layout -> Twitch Features:

It was a bit tricky to make sure the right elements get hidden, since all the rewards, power ups and category headlines are on the same level in hierarchy and don't have any classes to make them unique. Furthermore depending on if a challenge or prediction are active an additional div for the category "Challenges and Predictions" can be existent or not (the divs for the actual challenge or prediction are always existing, just the one for the header is optional). With the implementation I chose it should always hide the correct divs regardless of that.

Reward menu with power ups:

Reward menu with power ups and active prediction:

Reward menu without power ups:

Reward menu without power ups and active prediction:

[Excellify]

Gonna close as this will result in unwanted behaviour if twitch decide to change anything