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

ReactCommon/ReactCommon.podspec

@@ -19,7 +19,7 @@ end
 folly_compiler_flags = '-DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -Wno-comma -Wno-shorten-64-to-32 -Wno-gnu-zero-variadic-macro-arguments'
 folly_version = '2021.07.22.00'
 boost_compiler_flags = '-Wno-documentation'
-
+using_hermes = ENV['USE_HERMES'] == nil || ENV['USE_HERMES'] == "1"
 Pod::Spec.new do |s|
   s.name                   = "ReactCommon"
   s.module_name            = "ReactCommon"
@@ -49,6 +49,9 @@ Pod::Spec.new do |s|
     s.dependency "React-logger", version
     ss.dependency "DoubleConversion"
     ss.dependency "glog"
+    if using_hermes
+      ss.dependency "hermes-engine"
+    end
 
     ss.subspec "bridging" do |sss|
       sss.dependency           "React-jsi", version
@@ -56,6 +59,9 @@ Pod::Spec.new do |s|
       sss.exclude_files        = "react/bridging/tests"
       sss.header_dir           = "react/bridging"
       sss.pod_target_xcconfig  = { "HEADER_SEARCH_PATHS" => "\"$(PODS_TARGET_SRCROOT)/ReactCommon\" \"$(PODS_ROOT)/RCT-Folly\"" }
+      if using_hermes
+        sss.dependency "hermes-engine"
+      end
     end
 
     ss.subspec "core" do |sss|