Restore Dynamic framework with Hermes in the Old Architecture

Summary:
I discovered that 0.69 could run React Native as Dynamic framework with Hermes and starting from 0.70 that's not possible anymore.
This diff restore that possibility.

Notice that now Hermes provisdes JSI and Dynamic Frameworks requires that all the dependencies are explicitly defined, therefore, whenever we have a pod that depended on `React-jsi`, now it also has to explicitly depends on `hermes-engine`

## Changelog
[iOS][Fixed] - Add Back dynamic framework support for the Old Architecture with Hermes

Reviewed By: cortinico

Differential Revision: D42829728

fbshipit-source-id: a660e3b1e346ec6cf3ceb8771dd8bceb0dbcb13a

React-Core.podspec

@@ -75,12 +75,20 @@ Pod::Spec.new do |s|
 
   s.subspec "Default" do |ss|
     ss.source_files           = "React/**/*.{c,h,m,mm,S,cpp}"
-    ss.exclude_files          = "React/CoreModules/**/*",
-                                "React/DevSupport/**/*",
-                                "React/Fabric/**/*",
-                                "React/FBReactNativeSpec/**/*",
-                                "React/Tests/**/*",
-                                "React/Inspector/**/*"
+    exclude_files = [
+      "React/CoreModules/**/*",
+      "React/DevSupport/**/*",
+      "React/Fabric/**/*",
+      "React/FBReactNativeSpec/**/*",
+      "React/Tests/**/*",
+      "React/Inspector/**/*"
+    ]
+    # If we are using Hermes (the default is use hermes, so USE_HERMES can be nil), we don't have jsc installed
+    # So we have to exclude the JSCExecutorFactory
+    if ENV['USE_HERMES'] == nil || ENV['USE_HERMES'] == "1"
+      exclude_files = exclude_files.append("React/CxxBridge/JSCExecutorFactory.{h,mm}")
+    end
+    ss.exclude_files = exclude_files
     ss.private_header_files   = "React/Cxx*/*.h"
   end
 
@@ -117,5 +125,8 @@ Pod::Spec.new do |s|
 
   if ENV['USE_HERMES'] == "0"
     s.dependency 'React-jsc'
+  else
+    s.dependency 'React-hermes'
+    s.dependency 'hermes-engine'
   end
 end