Fix #3735: Add search button doesn't resize correctly when moving between text fields

[soner-yuksel]

Changing view responder method to satisfy new refresh control condition and fixing trailing button bug in iPad

Summary of Changes

This pull request fixes #3735

Submitter Checklist:

• Unit Tests are updated to cover new or changed functionality
• User-facing strings use NSLocalizableString()

Test Plan:

Visit GitHub and open search to bring up keyboard
Use Up/Down arrow keys to move between text fields
Disabled add search button is not resized

Reviewer Checklist:

• Issues include necessary QA labels:
  • QA/(Yes|No)
  • bug / enhancement
• Necessary security reviews have taken place.
• Adequate unit test coverage exists to prevent regressions.
• Adequate test plan exists for QA to validate (if applicable).
• Issue and pull request is assigned to a milestone (should happen at merge time).