Bridgeless mode: Stop register JSTimers as callable JavaScript module

Summary:
We do not need to register JSTimers as a callable JavaScript module in bridgeless mode.

How we know bridgeless mode doesn't use JSTimers: [xbgs JSTimers](https://fburl.com/code/clbz47j5)

## Details: iOS
JSTimers is only called into [by RCTCxxBridge](https://www.internalfb.com/code/fbsource/[88911d726fb4413765903c32a9077cd662ee7b6e]/xplat/js/react-native-github/React/CxxBridge/RCTCxxBridge.mm?lines=1471), and [RCTTiming.mm, which uses the RCTBridge](https://www.internalfb.com/code/fbsource/[88911d726fb4413765903c32a9077cd662ee7b6e]/xplat/js/react-native-github/React/CoreModules/RCTTiming.mm?lines=23%2C241%2C264). RCTBridge is unavailable in bridgeless mode.

## Details: Android
JSTimers is only called into [by TimingModule, inside its BridgeTimerExecutor](https://www.internalfb.com/code/fbsource/[88911d726fb4413765903c32a9077cd662ee7b6e]/xplat/js/react-native-github/ReactAndroid/src/main/java/com/facebook/react/modules/core/TimingModule.java?lines=31%2C40%2C49). This BridgeTimerExecutor is [passed to TimingModule's JavaTimerManager](https://www.internalfb.com/code/fbsource/[88911d726fb4413765903c32a9077cd662ee7b6e]/xplat/js/react-native-github/ReactAndroid/src/main/java/com/facebook/react/modules/core/TimingModule.java?lines=61-66).

The Bridgeless React instance on Android **does not** use this TimingModule, or this BridgeTimerExecutor. Instead, the Bridgeless React instance [creates its own JavaTimerManager](https://www.internalfb.com/code/fbsource/[88911d726fb4413765903c32a9077cd662ee7b6e]/fbandroid/java/com/facebook/venice/ReactInstance.java?lines=118-123), [in C++](https://www.internalfb.com/code/fbsource/[88911d726fb4413765903c32a9077cd662ee7b6e]/fbandroid/java/com/facebook/venice/ReactInstance.java?lines=117%2C121%2C382), that [implements the callTimers APIs in C++](https://www.internalfb.com/code/fbsource/[88911d726fb4413765903c32a9077cd662ee7b6e]/fbandroid/java/com/facebook/venice/jni/JJSTimerExecutor.cpp?lines=18-22). Therefore, in Bridgeless mode, the React instance calls into TimerManager to execute timers, whereas in Bridge mode, TimingModule calls into JSTimers to call timers. Hence, JSTimers should also not be used in bridgeless mode.

Changelog: [Internal]

Reviewed By: fkgozali

Differential Revision: D37208873

fbshipit-source-id: ef6ebe0e8a9fcbcc1f8403ed40ff94ec00b2beac

Libraries/Core/setUpBatchedBridge.js

@@ -32,7 +32,9 @@ if (global.RN$Bridgeless === true && global.RN$registerCallableModule) {
 }
 
 registerModule('Systrace', () => require('../Performance/Systrace'));
-registerModule('JSTimers', () => require('./Timers/JSTimers'));
+if (!(global.RN$Bridgeless === true)) {
+  registerModule('JSTimers', () => require('./Timers/JSTimers'));
+}
 registerModule('HeapCapture', () => require('../HeapCapture/HeapCapture'));
 registerModule('SamplingProfiler', () =>
   require('../Performance/SamplingProfiler'),