Show keyboard upon entry

[zwarm]

Fixes #12084

This PR sets focus on the search input field and opens the keyboard upon entry to the search domain view. The SiteCreationSearchInputUIState now includes a showKeyboard field, so if for someone reason we don't want to show the keyboard on open we just need to set the field to false.

To test:

1. On "My site" choose "switch site"
2. Choose "Create WordPress.com site
3. Choose any kind of site
4. On entry to the domain search screen, the focus should be on the input text and the keyboard should be showing

NOTE: Existing behavior leaves keyboard open at all times incase the user wants to add or remove characters in the search field. If this changes, we can easily modify the code to close the keyboard as well.

PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

You can trigger optional UI/connected tests for these changes by visiting CircleCI here.

[peril-wordpress-mobile]

You can test the changes on this Pull Request by downloading the APK here.

[malinajirka]

Thanks @zwarm! LGTM.

The keyboard is re-shown after a configuration change. But I don't think it's an issue.

[zwarm]

The keyboard is re-shown after a configuration change. But I don't think it's an issue.

Yes, and I noticed it too and should have added that bit into the existing code note. My apologies. Supposedly in Android 11 there will be a way to detect if the keyboard is open. 🤞 Thanks for the review