Image Claims: minimum layout shift on desktop layout

## Issue
6068

## Change
Lock all images to fit a 16:9 container. We have implemented 'ZoomableImg', so no reason in trying to display in full size.

This reduces CLS from 0.4xx to 0.01x.

## Flaws
CLS could probably be zero if not for the spinner shifting things slightly. Also, mobile CLS is 0.07.

The troublesome part in this PR is that FileRenderInitiator, FileRender and their subcomponents are broken apart and it's hard to synchronize their visibility and size. There are time gaps where none of them are visible, etc.

This PR only tackles the major part (most bang for buck), which is the elimination of variable height of the rendered image.

## Aside
I think `claimIsMine` is unused, so don't waste time requesting it.

ui/page/file/index.js

@@ -8,7 +8,6 @@ import {
   makeSelectClaimIsNsfw,
   SETTINGS,
   makeSelectTagInClaimOrChannelForUri,
-  makeSelectClaimIsMine,
   makeSelectClaimIsStreamPlaceholder,
   makeSelectCollectionForId,
   COLLECTIONS_CONSTS,
@@ -35,7 +34,6 @@ const select = (state, props) => {
     renderMode: makeSelectFileRenderModeForUri(props.uri)(state),
     videoTheaterMode: makeSelectClientSetting(SETTINGS.VIDEO_THEATER_MODE)(state),
     commentsDisabled: makeSelectTagInClaimOrChannelForUri(props.uri, DISABLE_COMMENTS_TAG)(state),
-    claimIsMine: makeSelectClaimIsMine(props.uri)(state),
     isLivestream: makeSelectClaimIsStreamPlaceholder(props.uri)(state),
     collection: makeSelectCollectionForId(collectionId)(state),
     collectionId,

ui/page/file/view.jsx

@@ -115,6 +115,18 @@ function FilePage(props: Props) {
       );
     }
 
+    if (renderMode === RENDER_MODES.IMAGE) {
+      return (
+        <React.Fragment>
+          <div className="file-render--img-container">
+            <FileRenderInitiator uri={uri} />
+            <FileRenderInline uri={uri} />
+          </div>
+          <FileTitleSection uri={uri} />
+        </React.Fragment>
+      );
+    }
+
     return (
       <React.Fragment>
         <FileRenderInitiator uri={uri} videoTheaterMode={videoTheaterMode} />

ui/scss/component/_file-render.scss

@@ -100,6 +100,11 @@
   max-height: none;
 }
 
+.file-render--img-container {
+  width: 100%;
+  aspect-ratio: 16 / 9;
+}
+
 .file-render__header {
   display: flex;
   justify-content: space-between;