Do not add HOTSEAT_ICONS to visible elements for device type "phone" in

ALL_APPS State

HOTSEAT_ICONS got added to visible elements for ALL_APPS State in ag/16992837.

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Phone
Before:
HotSeat present in view hierarchy - https://hsv.googleplex.com/4906040983289856?node=41
Video: https://b.corp.google.com/issues/228803923#comment9

After:
HotSeat not present in view hierarchy - https://hsv.googleplex.com/5379653922455552?node=42
Video: https://b.corp.google.com/issues/228803923#comment11
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Tablets

I couldn't test this implementation on tablet. But I have verified on a phone
locally by adding HOTSEAT_ICONS to visible elements and then verifying
"IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS" get set and hotseat icons are not focusable in all apps.
Video : https://b.corp.google.com/issues/228803923#comment14

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Bug: 228803923
Bug: 227565451

Test: Manual. See the video attached in bug.
Change-Id: I055e3bb61c8cfd240e0fe1000fe3a391a150f6d1