do not shrink SessionSpinner

stylesheets/_session.scss

@@ -801,6 +801,7 @@ label {
   position: relative;
   width: 80px;
   height: 80px;
+  flex-shrink: 0;
 
   div {
     position: absolute;

ts/components/session/SessionClosableOverlay.tsx

@@ -168,6 +168,8 @@ export class SessionClosableOverlay extends React.Component<Props, State> {
       overlayMode === SessionClosableOverlayType.ClosedGroup &&
       contacts.length === 0;
 
+    const showLoadingSpinner = showSpinner === undefined ? false : showSpinner;
+
     return (
       <div className="module-left-pane-overlay">
         <div className="exit">
@@ -211,7 +213,7 @@ export class SessionClosableOverlay extends React.Component<Props, State> {
           />
         )}
 
-        {showSpinner && <SessionSpinner />}
+        <SessionSpinner loading={showLoadingSpinner} />
 
         {isClosedGroupView && (
           <>

ts/components/session/SessionSpinner.tsx

@@ -1,32 +1,22 @@
 import React from 'react';
 
-interface Props {
+type Props = {
   loading: boolean;
-}
+};
 
-export class SessionSpinner extends React.Component<Props> {
-  public static defaultProps = {
-    loading: true,
-  };
+export const SessionSpinner = (props: Props) => {
+  const { loading } = props;
 
-  constructor(props: any) {
-    super(props);
-  }
-
-  public render() {
-    const { loading } = this.props;
-
-    return (
-      <>
-        {loading ? (
-          <div className="session-loader">
-            <div />
-            <div />
-            <div />
-            <div />
-          </div>
-        ) : null}
-      </>
-    );
-  }
-}
+  return (
+    <>
+      {loading ? (
+        <div className="session-loader">
+          <div />
+          <div />
+          <div />
+          <div />
+        </div>
+      ) : null}
+    </>
+  );
+};