More Label touchups (margins) (#10722)

* labels with onClick don't need .pointer. No labels need `m-r-5`

* making Timer a proper Label

* a little linting

* addresing (helpful, thanks) comment

superset-frontend/src/explore/components/controls/FixedOrMetricControl.jsx

@@ -104,7 +104,7 @@ export default class FixedOrMetricControl extends React.Component {
     return (
       <div>
         <ControlHeader {...this.props} />
-        <Label className="pointer" onClick={this.toggle}>
+        <Label onClick={this.toggle}>
           {this.state.type === controlTypes.fixed && (
             <span>{this.state.fixedValue}</span>
           )}