feat: add a tooltip to clarify metric_name in the DatasetEditor (#24348)

superset-frontend/src/components/Datasource/DatasourceEditor.jsx

@@ -182,10 +182,10 @@ function ColumnCollectionTable({
   allowAddItem,
   allowEditDataType,
   itemGenerator,
+  columnLabelTooltips,
 }) {
   return (
     <CollectionTable
-      collection={columns}
       tableColumns={
         isFeatureEnabled(FeatureFlag.ENABLE_ADVANCED_DATA_TYPES)
           ? [
@@ -229,6 +229,8 @@ function ColumnCollectionTable({
       allowDeletes
       allowAddItem={allowAddItem}
       itemGenerator={itemGenerator}
+      collection={columns}
+      columnLabelTooltips={columnLabelTooltips}
       stickyHeader
       expandFieldset={
         <FormContainer>
@@ -1194,10 +1196,17 @@ class DatasourceEditor extends React.PureComponent {
         tableColumns={['metric_name', 'verbose_name', 'expression']}
         sortColumns={['metric_name', 'verbose_name', 'expression']}
         columnLabels={{
-          metric_name: t('Metric'),
+          metric_name: t('Metric Key'),
           verbose_name: t('Label'),
           expression: t('SQL expression'),
         }}
+        columnLabelTooltips={{
+          metric_name: t(
+            'This field is used as a unique identifier to attach ' +
+              'the metric to charts. It is also used as the alias in the ' +
+              'SQL query.',
+          ),
+        }}
         expandFieldset={
           <FormContainer>
             <Fieldset compact>
@@ -1417,6 +1426,13 @@ class DatasourceEditor extends React.PureComponent {
                 onColumnsChange={calculatedColumns =>
                   this.setColumns({ calculatedColumns })
                 }
+                columnLabelTooltips={{
+                  column_name: t(
+                    'This field is used as a unique identifier to attach ' +
+                      'the calculated dimension to charts. It is also used ' +
+                      'as the alias in the SQL query.',
+                  ),
+                }}
                 onDatasourceChange={this.onDatasourceChange}
                 datasource={datasource}
                 editableColumnName