fix: fix a typo in the react_native_pods.rb file (#53129)

Summary:
- Switches fmt_config to fast_float_config so it matches what is used in the method

When trying to use a forked version of the Pod it is not possible to set a new repo for Fast Float. This was caused by a typo in the method used to update the configuration of where to find the Pod.

## Changelog:

[IOS] [FIXED] - Fixed variable naming error in set_fast_float_config method in react_native_pods.rb

Pull Request resolved: #53129

Test Plan: Add the line `set_fast_float_config({:git => 'some-git-repo'})` to an application's Podfile

Reviewed By: cortinico

Differential Revision: D79805939

Pulled By: cipolleschi

fbshipit-source-id: 9705e1f63e21b788362ca94b74e32bce0177a729

Author: eliotfallon213

packages/react-native/scripts/react_native_pods.rb

@@ -377,7 +377,7 @@ def set_glog_config(glog_config)
 
 # This method can be used to set the fast_float config
 # that can be used to configure libraries.
-def set_fast_float_config(fmt_config)
+def set_fast_float_config(fast_float_config)
   Helpers::Constants.set_fast_float_config(fast_float_config)
 end