Fix youtube ads (white-page pre-rolls) in IOS

[ryanbr]

Description:

Youtube ads are still being shown on IOS. reported by @cacevedo222

Actual result:

Additional Information

From implementing json-prune.js in: #2655 we should also implement set.js for ios to prevent these white-screen pre-roll ads.

I implemented the following js snippet in brave-unbreak to prevent these ads in brave/adblock-lists#420 Which seems to help prevent these ads from showing up.

youtube.com##+js(set, ytInitialPlayerResponse.adPlacements, undefined)
youtube.com##+js(set, adPlacements, undefined)

set.js source: https://github.com/brave/uBlock/blob/525d10a489ba832e212f54d11994ffef12fadfe4/assets/resources/scriptlets.js#L589

@Brandon-T

[srirambv]

Verification passed on iPhone 7+ with iOS 14.0.1 running 1.21(20.10.06.20)

• Verified no pre-roll ads shown when loading YT videos
• Verified on both normal and private tabs

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Verification passed on iPhone XR with iOS 13.5 running 1.21(20.10.06.20)

• Verified no pre-roll ads shown when loading YT videos
• Verified on both normal and private tabs

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Verification passed on iPad Pro with iOS 14.0.1 running 1.21(20.10.06.20)

• Verified no pre-roll ads shown when loading YT videos
• Verified on both normal and private tabs

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Verification passed on iPad Pro with iOS 12.4.1 running 1.21(20.10.06.20)

• Verified no pre-roll ads shown when loading YT videos
• Verified on both normal and private tabs