The Filter field is still available, but requires an additional step in the user-interface to reveal it.
Every column now has a column menu which is available by mouse-over or hover-over, but may be hidden if the column width is too narrow.
Enable Filter visibility through the column menu (for any column) and check the “Top toolbar” option.
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Note that this is not a sticky option, so if the page is re-loaded the toolbar will be hidden again.