Add enableComponentStackLocations to ReactNativeInternalFeatureFlags libdef (#28424)

## Summary

Fixing something I accidentally broke this in
25dbb35.

## How did you test this change?

Ran the following successfully:

```
$ yarn flow dom-node
```

Author: yungsters

scripts/flow/xplat.js

@@ -9,6 +9,7 @@
 
 declare module 'ReactNativeInternalFeatureFlags' {
   declare export var alwaysThrottleRetries: boolean;
+  declare export var enableComponentStackLocations: boolean;
   declare export var enableDeferRootSchedulingToMicrotask: boolean;
   declare export var enableUseRefAccessWarning: boolean;
   declare export var passChildrenWhenCloningPersistedNodes: boolean;