Revert "Disable Impeller when the manifest explicitly disables it (#53108)"

This reverts commit 8da25dc953a030551fe32b91d7ae4ec08c70760f.

shell/platform/android/io/flutter/embedding/engine/loader/FlutterLoader.java

diff --git a/shell/platform/android/io/flutter/embedding/engine/loader/FlutterLoader.java b/shell/platform/android/io/flutter/embedding/engine/loader/FlutterLoader.java
index c720f37..b540c20 100644
--- a/shell/platform/android/io/flutter/embedding/engine/loader/FlutterLoader.java
+++ b/shell/platform/android/io/flutter/embedding/engine/loader/FlutterLoader.java
@@ -340,10 +340,8 @@
       shellArgs.add("--prefetched-default-font-manager");
 
       if (metaData != null) {
-        if (metaData.getBoolean(ENABLE_IMPELLER_META_DATA_KEY, true)) {
+        if (metaData.getBoolean(ENABLE_IMPELLER_META_DATA_KEY, false)) {
           shellArgs.add("--enable-impeller");
-        } else {
-          shellArgs.add("--enable-impeller=false");
         }
         if (metaData.getBoolean(ENABLE_VULKAN_VALIDATION_META_DATA_KEY, false)) {
           shellArgs.add("--enable-vulkan-validation");