* Grafana/UI: Add disable prop to Segment

SegmentSync, SegmentAsync and SegmentInput had the disable prop inherited from HTMLProp but it did not disable the component. The disable prop should now disable the component.

* Use InlineLabel instead of span and remove some sass-classes in Segments

* Change MetricsQueryEditor test to reflect new layout of AsyncSegment

* Use useStyles hook to get themed styles for segment inputs

Co-authored-by: Alex Khomenko <Clarity-89@users.noreply.github.com>