Add DEFINES_MODULE=YES to the yoga podspec (#26276)

Summary:
This fixes an error when using RN's version of yoga with Flipper.

```
[!] The following Swift pods cannot yet be integrated as static libraries:

The Swift pod `YogaKit` depends upon `Yoga`, which does not define modules. To opt into those targets generating module maps (which is necessary to import them from Swift when building as static libraries), you may set `use_modular_headers!` globally in your Podfile, or specify `:modular_headers => true` for particular dependencies.
```

Taken from https://github.com/facebook/yoga/blob/master/Yoga.podspec#L25

## Changelog

[Internal] [Fixed] - Add `DEFINES_MODULE=YES` to the yoga podspec
Pull Request resolved: #26276

Reviewed By: priteshrnandgaonkar

Differential Revision: D17149819

Pulled By: axe-fb

fbshipit-source-id: 5060b8e7111ba411f6e26e3479ad4fb55a552b4e

ReactCommon/yoga/yoga.podspec

@@ -29,6 +29,9 @@ Pod::Spec.new do |spec|
 
   spec.module_name = 'yoga'
   spec.requires_arc = false
+  spec.pod_target_xcconfig = {
+      'DEFINES_MODULE' => 'YES'
+  }
   spec.compiler_flags = [
       '-fno-omit-frame-pointer',
       '-fexceptions',