Remove imports of React that are no longer needed (#1531)

src/components/Login/RegisterPage/tests/RegisterComponent.test.tsx

@@ -1,4 +1,3 @@
-import React from "react";
 import ReactDOM from "react-dom";
 import renderer, {
   ReactTestInstance,

src/components/Toast/UpperRightToastContainer.tsx

@@ -1,11 +1,11 @@
-import React from "react";
+import { ReactElement } from "react";
 import { ToastContainer } from "react-toastify";
 // Styles the ToastContainer so that it appears on the upper right corner with the message.
 import "react-toastify/dist/ReactToastify.min.css";
 
 /** A pre-configured ToastContainer to consistently display toasts in the
  * upper right corner of the screen. */
-export function UpperRightToastContainer() {
+export function UpperRightToastContainer(): ReactElement {
   return (
     <ToastContainer
       position="top-right"

src/goals/ReviewEntries/ReviewEntriesComponent/CellComponents/SenseCell.tsx

@@ -1,6 +1,6 @@
 import { Chip, IconButton } from "@material-ui/core";
 import { Add, Delete, RestoreFromTrash } from "@material-ui/icons";
-import React, { ReactElement } from "react";
+import { ReactElement } from "react";
 
 import AlignedList from "goals/ReviewEntries/ReviewEntriesComponent/CellComponents/AlignedList";
 import { FieldParameterStandard } from "goals/ReviewEntries/ReviewEntriesComponent/CellComponents/CellColumns";