Avoid showing Zh-TW and Zh-CN keyboard candidate view when typing symbols.

[daoshengmu]

Fixes #3506.

When typing symbols, we can just use AUTO_COMPOSE mode.

I was trying to make Zh-CN and JPN keyboard have the same behavior when typing symbols, using AUTO_COMPOSE instead of SHOW_CANDIDATES. But, JPN keyboard will show ． when inserting /。The only way possible is fixing their code book to avoid it, but it is not worth to do. IMO, We can still rely on their code book to feed our data, iOS JPN keyboard uses the same behavior either.

[keianhzo]

@daoshengmu This PR makes the Zh-CN and Zh-TW differ in the way they show candidates for symbols. Pinyin shows the candidate view for symbols and Zhuyin doesn't. For what I see in the GBoard for both Pinyin and Zhuyin showing the symbols keyboard hides the candidate view automatically, maybe we should unify that also in our Chinese keyboards? Japanese on the other side composes and keeps the candidate view opened when adding symbols.

Also I'm getting a crash in the Zhuyin keyboard when typing characters and adding a symbol after that:

java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
        at org.mozilla.vrbrowser.ui.widgets.KeyboardWidget.updateCandidates(KeyboardWidget.java:4)
        at org.mozilla.vrbrowser.ui.widgets.KeyboardWidget.handleText(KeyboardWidget.java:20)
        at org.mozilla.vrbrowser.ui.widgets.KeyboardWidget.onKey(KeyboardWidget.java:34)
        at org.mozilla.vrbrowser.ui.views.CustomKeyboardView.detectAndSendKey(CustomKeyboardView.java:20)
        at org.mozilla.vrbrowser.ui.views.CustomKeyboardView.onModifiedTouchEvent(CustomKeyboardView.java:61)
        at org.mozilla.vrbrowser.ui.views.CustomKeyboardView.onTouchEvent(CustomKeyboardView.java:15)
        at android.view.View.dispatchTouchEvent(View.java:13415)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3060)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2755)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3060)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2755)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3060)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2755)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3060)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2755)
        at org.mozilla.vrbrowser.ui.widgets.UIWidget.handleTouchEvent(UIWidget.java:1)
        at org.mozilla.vrbrowser.input.MotionEventGenerator.generateEvent(MotionEventGenerator.java:8)
        at org.mozilla.vrbrowser.input.MotionEventGenerator.generateEvent(MotionEventGenerator.java:1)
        at org.mozilla.vrbrowser.input.MotionEventGenerator.dispatch(MotionEventGenerator.java:36)
        at org.mozilla.vrbrowser.VRBrowserActivity.lambda$handleMotionEvent$21$VRBrowserActivity(VRBrowserActivity.java:8)
        at org.mozilla.vrbrowser.-$$Lambda$VRBrowserActivity$m-PcHRm-UE8sfHU3H9lbI4GkhBc.run(Unknown Source:14)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

[daoshengmu]

It should be solved. I have made Zh-CN and Zh-TW have consistent behaviors.

[keianhzo]

Looks consistent now