Properly expose jscexecutor as a prefab target (facebook#35521)

Summary:
Pull Request resolved: facebook#35521

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: 1a04bc21aa50eece304828ce1d99ae795a51af48

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 {