In an Entry the KeyUp and KeyDown events do not fire for some keys on the numeric pad

[SMerrony]

Describe the bug:

In an Entry the KeyUp and KeyDown events do not fire for some keys on the numeric pad.

To Reproduce:

Steps to reproduce the behaviour:

1. Run the code below which is a slightly modified version of keypress-on-entry from the Fyne tutorial
2. Hit 1 on the keypad - it shows in the widget, but the KeyUp() and KeyDown() events do not occur
3. Hit (forward) slash on the keypad - it shows in the widget and both event occur as expected

Example code:

package main

import (
	"fmt"

	"fyne.io/fyne"
	"fyne.io/fyne/app"
	"fyne.io/fyne/widget"
)

type enterEntry struct {
	widget.Entry
}

func (e *enterEntry) onEnter() {
	fmt.Println(e.Entry.Text)
	e.Entry.SetText("")
}

func newEnterEntry() *enterEntry {
	entry := &enterEntry{}
	entry.ExtendBaseWidget(entry)
	return entry
}

func (e *enterEntry) KeyDown(key *fyne.KeyEvent) {
	switch key.Name {
	case fyne.KeyReturn:
		e.onEnter()
	default:
		e.Entry.KeyDown(key)
		fmt.Printf("Key %v pressed\n", key.Name)
	}
}

func (e *enterEntry) KeyUp(key *fyne.KeyEvent) {
	fmt.Printf("Key %v released\n", key.Name)
}

func main() {
	a := app.New()
	w := a.NewWindow("Messenger")

	entry := newEnterEntry()

	w.SetContent(entry)
	w.ShowAndRun()
}

Device (please complete the following information):

• OS: Linux
• Version: Mint LMDE 4 Debbie
• Go version: 1.14.4
• Fyne version: 1.3.3 (? installed via go get last week)

[andydotxyz]

Fix is on develop for testing