Focus text input in prompt dialog

[srgpqt]

Platforms affected

Android 10

Motivation and Context

Some versions of Android 10 SDK do not automatically focus the EditText control, resulting in a blank, unbordered, input box which is essentially invisible.

Description

Added 1 line to focus the EditText input in the prompt method.

Testing

Tested the fix in the android 10 simulator.

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[Thul999]

This was not working for me, but I added a couple of lines and now it seems to be working fine #139