Enable lint rules for Promise handling to discourage misuse of them. (#2607)

* Enable lint rules for Promise handling to discourage misuse of them.
Squashed all of Hugh's commits into one.

---------

Co-authored-by: Hugh Nimmo-Smith <hughns@element.io>

src/grid/Grid.tsx

@@ -32,6 +32,7 @@ import {
 } from "react";
 import useMeasure from "react-use-measure";
 import classNames from "classnames";
+import { logger } from "matrix-js-sdk/src/logger";
 
 import styles from "./Grid.module.css";
 import { useMergedRefs } from "../useMergedRefs";
@@ -353,7 +354,7 @@ export function Grid<
   // Because we're using react-spring in imperative mode, we're responsible for
   // firing animations manually whenever the tiles array updates
   useEffect(() => {
-    springRef.start();
+    springRef.start().forEach((p) => void p.catch(logger.error));
   }, [placedTiles, springRef]);
 
   const animateDraggedTile = (
@@ -390,7 +391,8 @@ export function Grid<
                 ((key): boolean =>
                   key === "zIndex" || key === "x" || key === "y"),
             },
-      );
+      )
+      .catch(logger.error);
 
     if (endOfGesture)
       callback({