[DataGrid] Use explicit definition instead of React.FC

[m4theushw]

• I have searched the issues of this repository and believe that this is not a duplicate.

Summary 💡

We're typing many components with React.FC. One of the problems with this approach is that it provides an implicit definition of the children prop, even for those components that don't use it. We should favor an explicit definition instead.

diff --git a/packages/grid/_modules_/grid/components/GridRowCount.tsx b/packages/grid/_modules_/grid/components/GridRowCount.tsx
index 4d888ce..45ca4a3 100644
--- a/packages/grid/_modules_/grid/components/GridRowCount.tsx
+++ b/packages/grid/_modules_/grid/components/GridRowCount.tsx
@@ -1,7 +1,11 @@
 import * as React from 'react';
 import { GridApiContext } from './GridApiContext';

-export const GridRowCount: React.FC<{ rowCount: number }> = ({ rowCount }) => {
+export interface GridRowCountProps {
+  rowCount: number
+}
+
+export const GridRowCount = (props: GridRowCountProps) => {
+  const { rowCount } = props;
   const apiRef = React.useContext(GridApiContext);

   if (rowCount === 0) {