[FIX-#2327] Revert deletion of hide css class in process of angular upgrade

[stanisev]

Reverting back .hide css class, since delete button should be displayed only when an item is hovered and hidden and not all the time.

[CLAassistant]

All committers have signed the CLA.

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[coveralls]

coverage: 83.347%. remained the same when pulling ed6291d3d75721d778e9f02692613848c989b1e3 on stanisev:fix/#2327-revert-hide-css-deletion into 718aba099aa892f8266cdef0752a02dc4bb7124f on eclipsesource:master.