Bugfix/mob 680 keyboard is not hidden when leaving validation flow

[FredericoSantinho]

What does this PR do?

Fix bug that caused keyboard to keep showing after user presses back in CodeValidationFragment.

Database changed?

No

Where should the reviewer start?

• [ ] BaseActivity.java

How should this be manually tested?

Start the wallet validation flow, enter a valid number and press next; when the input for the received PIN is shown, press the "Back" arrow in the toolbar.

What are the relevant tickets?

Tickets related to this pull-request: MOB-680

Questions:

Does this add new dependencies which need to be added? (Eg. new libs, new keys, etc.)

No

Code Review Checklist

• [ ] Architecture
• [ ] Documentation on public interfaces
• [ ] Database changed?
• [ ] If yes - Database migration?
• [ ] Remove comments & unused code & forgotten testing Logs
• [ ] Codestyle
• [ ] Functional QA tests pass