Properly expose jscexecutor as a prefab target

Summary:
Inside RC3 the jscexecutor target was prepared for prefab consumption
but not properly exposed.
This was not caught by the CI as we're not effectively using this target,
but some of our popular libraries do (i.e. Reanimated). I'm exposing it here.

Changelog:
[Internal] [Changed] - Properly expose `jscexecutor` as a prefab target

Reviewed By: javache

Differential Revision: D41648349

fbshipit-source-id: 499d54b4ff219024690eb80f8ddcebd9708a7ac2

Author: cortinico

ReactAndroid/build.gradle

@@ -435,8 +435,7 @@ android {
                     "-DANDROID_TOOLCHAIN=clang",
                     "-DANDROID_PLATFORM=android-21"
 
-                targets "jscexecutor",
-                    "jsijniprofiler",
+                targets "jsijniprofiler",
                     "reactnativeblob",
                     "reactperfloggerjni",
                     // prefab targets
@@ -463,7 +462,8 @@ android {
                     "react_render_uimanager",
                     "react_render_scheduler",
                     "react_render_mounting",
-                    "hermes_executor"
+                    "hermes_executor",
+                    "jscexecutor"
             }
         }
         ndk {
@@ -583,6 +583,9 @@ android {
         hermes_executor {
             headers(new File(prefabHeadersDir, "hermes_executor").absolutePath)
         }
+        jscexecutor {
+            headers(new File(prefabHeadersDir, "jscexecutor").absolutePath)
+        }
     }
 
     publishing {