[SPARK-31967][UI] Downgrade to vis.js 4.21.0 to fix Jobs UI loading time regression

### What changes were proposed in this pull request?

After apache#28192, the job list page becomes very slow.
For example, after the following operation, the UI loading can take >40 sec.
```
(1 to 1000).foreach(_ => sc.parallelize(1 to 10).collect)
```

This is caused by a  [performance issue of `vis-timeline`](visjs/vis-timeline#379). The serious issue affects both branch-3.0 and branch-2.4

I tried a different version 4.21.0 from https://cdnjs.com/libraries/vis
The infinite drawing issue seems also fixed if the zoom is disabled as default.

### Why are the changes needed?

Fix the serious perf issue in web UI by falling back vis-timeline-graph2d to an ealier version.

### Does this PR introduce _any_ user-facing change?

Yes, fix the UI perf regression

### How was this patch tested?

Manual test

Closes apache#28806 from gengliangwang/downgradeVis.

Authored-by: Gengliang Wang <[email protected]>
Signed-off-by: Gengliang Wang <[email protected]>

Author: gengliangwang

core/src/main/resources/org/apache/spark/ui/static/vis-timeline-graph2d.min.css

@@ -31,9 +31,7 @@ dagre-d3.min.js
 graphlib-dot.min.js
 sorttable.js
 vis-timeline-graph2d.min.js
-vis-timeline-graph2d.min.js.map
 vis-timeline-graph2d.min.css
-vis-timeline-graph2d.min.css.map
 dataTables.bootstrap4.1.10.20.min.css
 dataTables.bootstrap4.1.10.20.min.js
 dataTables.rowsGroup.js

core/src/main/resources/org/apache/spark/ui/static/vis-timeline-graph2d.min.css.map

@@ -1,23 +1,22 @@
-vis-timeline and vis-graph2d
-https://visjs.github.io/vis-timeline/
+vis.js
+https://github.com/almende/vis
 
-Create a fully customizable, interactive timeline with items and ranges.
+A dynamic, browser-based visualization library.
 
-@version 7.3.4
-@date    2020-03-18T17:03:58.105Z
-
-@copyright (c) 2011-2017 Almende B.V, http://almende.com
-@copyright (c) 2017-2019 visjs contributors, https://github.com/visjs
+@version 4.20.1-SNAPSHOT
+@date    2017-10-12
 
 @license
-vis.js is dual licensed under both
+Copyright (C) 2011-2017 Almende B.V, http://almende.com
+
+Vis.js is dual licensed under both
 
-  1. The Apache 2.0 License
-     http://www.apache.org/licenses/LICENSE-2.0
+* The Apache 2.0 License
+  http://www.apache.org/licenses/LICENSE-2.0
 
-  and
+and
 
-  2. The MIT License
-     http://opensource.org/licenses/MIT
+* The MIT License
+  http://opensource.org/licenses/MIT
 
-vis.js may be distributed under either license.
+Vis.js may be distributed under either license.

core/src/main/resources/org/apache/spark/ui/static/vis-timeline-graph2d.min.js

@@ -1,23 +1,22 @@
-vis-timeline and vis-graph2d
-https://visjs.github.io/vis-timeline/
+vis.js
+https://github.com/almende/vis
 
-Create a fully customizable, interactive timeline with items and ranges.
+A dynamic, browser-based visualization library.
 
-@version 7.3.4
-@date    2020-03-18T17:03:58.105Z
-
-@copyright (c) 2011-2017 Almende B.V, http://almende.com
-@copyright (c) 2017-2019 visjs contributors, https://github.com/visjs
+@version 4.20.1-SNAPSHOT
+@date    2017-10-12
 
 @license
-vis.js is dual licensed under both
+Copyright (C) 2011-2017 Almende B.V, http://almende.com
+
+Vis.js is dual licensed under both
 
-  1. The Apache 2.0 License
-     http://www.apache.org/licenses/LICENSE-2.0
+* The Apache 2.0 License
+  http://www.apache.org/licenses/LICENSE-2.0
 
-  and
+and
 
-  2. The MIT License
-     http://opensource.org/licenses/MIT
+* The MIT License
+  http://opensource.org/licenses/MIT
 
-vis.js may be distributed under either license.
+Vis.js may be distributed under either license.