Remove getJSValue in favor of toJSValue

[tomekzaw]

Summary

Here's the current implementation of Shareable::getJSValue:

react-native-reanimated/Common/cpp/SharedItems/Shareables.h

Lines 91 to 93 in e661676

	virtual jsi::Value getJSValue(jsi::Runtime &rt) {
	return toJSValue(rt);
	}

This PR removes getJSValue in favor of toJSValue as well as updates all usages.

Test plan

Just run the Example app.