delete RCTJSScriptLoaderModule (#37284)

Summary:
Pull Request resolved: #37284

Changelog: [iOS][Removed]

in the past, we had this protocol so we could decorate the `RCTDevSplitBundleLoader`, which was removed by motiz88. now that doesn't exist anymore, we should delete this protocol. i did a quick grep on github and this protocol was only used by `RCTDevSplitBundleLoader`, so i don't think this will be a major breaking change

Reviewed By: christophpurrer

Differential Revision: D45591882

fbshipit-source-id: 23656d0c04fa4e1c4cfc65b1052d4c3614ba8708

packages/react-native/ReactCommon/react/bridgeless/platform/ios/Core/RCTInstance.mm

@@ -19,7 +19,6 @@
 #import <React/RCTDisplayLink.h>
 #import <React/RCTEventDispatcherProtocol.h>
 #import <React/RCTFollyConvert.h>
-#import <React/RCTJSScriptLoaderModule.h>
 #import <React/RCTJavaScriptLoader.h>
 #import <React/RCTLog.h>
 #import <React/RCTLogBox.h>
@@ -259,12 +258,6 @@ - (Class)getModuleClassFromName:(const char *)name
 - (void)_attachBridgelessAPIsToModule:(id<RCTTurboModule>)module FB_OBJC_DIRECT
 {
  __weak RCTInstance *weakInstance = self;
- if ([module respondsToSelector:@selector(setLoadScript:)]) {
- ((id<RCTJSScriptLoaderModule>)module).loadScript = ^(RCTSource *source) {
- [weakInstance loadScriptFromSource:(source)];
- };
- }
-
  if ([module respondsToSelector:@selector(setDispatchToJSThread:)]) {
  ((id<RCTJSDispatcherModule>)module).dispatchToJSThread = ^(dispatch_block_t block) {
  __strong __typeof(self) strongSelf = weakInstance;