[EmojiSuggest] Update fieldtrial testing config

Experiment with new maps.
Related CL: http://cl/332964764

Bug: b/166523259
Change-Id: I9ba8f3d637fb8b68cb3e776d3f5156156d4b53ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2423063Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: My Nguyen <myy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809631}

testing/variations/fieldtrial_testing_config.json

@@ -1504,9 +1504,9 @@
             ],
             "experiments": [
                 {
-                    "name": "UseMap1_20200903",
+                    "name": "UseMap2_20200922",
                     "params": {
-                        "map": "1"
+                        "map": "2"
                     },
                     "enable_features": [
                         "EmojiSuggestAddition"