Entry widget, position of cursor when clicking empty space

[kgolding]

Describe the bug:

Clicking in the empty space under and to the right of a line of text in a multiline Entry widget, results in the cursor jumping to the start of the line when typically a user would expect it to jump to the end of the text.

To Reproduce:

Steps to reproduce the behaviour:

1. Open a fyne app with a multiline widget
2. Enter a line of text
3. Position the mouse under and to the right of the line of text, but still within the Entry bounds and click
4. The cursor will jump to the start of the text when most users would expect it to jump to the end of the text

Device:

• OS: Linux
• Version: kubuntu 20.04
• Go version: 1.18
• Fyne version: v2.1.4

[andydotxyz]

Thanks for the fix @chrisbirster :)

[andydotxyz]

(On develop branch for testing)