fix(plugin-chart-ag-grid-table): select cell on click instead of its text (#106389)

enableCellTextSelection forced browser text selection when clicking a cell,
which suppressed AG Grid's cell-focus (cell selection) behavior. Disable it so a
click selects/focuses the cell as users expect.

Note: full multi-cell range selection requires AG Grid Enterprise and is not
available in the Community build, so the multi-cell part of the acceptance
criteria cannot be satisfied without an Enterprise license.

superset-frontend/plugins/plugin-chart-ag-grid-table/src/AgGridTable/index.tsx

@@ -520,7 +520,12 @@ const AgGridDataTable: FunctionComponent<AgGridTableProps> = memo(
           initialState={gridInitialState}
           maintainColumnOrder
           suppressAggFuncInHeader
-          enableCellTextSelection
+          // Clicking a cell should select (focus) the cell rather than select
+          // its text content (#106389). enableCellTextSelection forces browser
+          // text selection on click, which suppresses the cell-focus behavior.
+          // Full multi-cell range selection requires AG Grid Enterprise and is
+          // not available in the Community build used here.
+          enableCellTextSelection={false}
           quickFilterText={serverPagination ? '' : quickFilterText}
           suppressMovableColumns={!allowRearrangeColumns}
           pagination={pagination}