set issearchable default value to true

public/app/core/components/Select/MetricSelect.tsx

@@ -22,6 +22,7 @@ export class MetricSelect extends React.Component<Props, State> {
   static defaultProps = {
     variables: [],
     options: [],
+    isSearchable: true,
   };
 
   constructor(props) {

public/app/plugins/datasource/stackdriver/partials/query.aggregation.html

@@ -5,7 +5,6 @@
       onChange="ctrl.handleAggregationChange"
       value="ctrl.target.aggregation.crossSeriesReducer"
       options="ctrl.aggOptions"
-      is-searchable="true"
       placeholder="'Select Aggregation'"
       className="'width-15'"
       variables="ctrl.templateSrv.variables"
@@ -28,7 +27,6 @@
       onChange="ctrl.handleAlignmentChange"
       value="ctrl.target.aggregation.perSeriesAligner"
       options="ctrl.alignOptions"
-      is-searchable="true"
       placeholder="'Select Alignment'"
       className="'width-15'"
       variables="ctrl.templateSrv.variables"
@@ -45,7 +43,6 @@
       onChange="ctrl.handleAlignmentPeriodChange"
       value="ctrl.target.aggregation.alignmentPeriod"
       options="ctrl.alignmentPeriods"
-      is-searchable="true"
       placeholder="'Select Alignment'"
       className="'width-15'"
       variables="ctrl.templateSrv.variables"

public/app/plugins/datasource/stackdriver/partials/query.filter.html

@@ -21,7 +21,6 @@
       options="ctrl.getMetricsList()"
       variables="ctrl.templateSrv.variables"
       group-name="'Metric Types'"
-      is-searchable="true"
       placeholder="'Select Metric'"
       className="'width-15'"
     ></metric-select>