fix: allow bluring of disabled field

[haakandev]

Summary

When trying to blur and set a TextInput as disabled at the same time, the blur does not take effect.
Example use case:

• Form of TextInputs (and other inputs) where fields have their disabled prop set to true while submitting
• While a TextInput is focused, user clicks a submit button that sets the above mentioned prop to loading
  Expected: The TextInput is blurred
  Actual: The TextInput is not properly blurred and left in a semi-focused state (no keyboard and greyed out, but but showing thicker underline)

See https://snack.expo.io/r8Cpj71On for iOS/Android

1. Having the first TextInput focused when clicking the button works fine
2. Focusing the second TextInput and clicking the button leaves the TextInput with a thicker underline as it is still in focused state

This PR fixes this by removing the check on disabled prop in handleBlur. If this existed for some other purpose, please let me know and maybe there's a different solution.

Test plan

See Snack above for testing

[callstack-bot]

Hey @haakandev, thank you for your pull request 🤗. The documentation from this branch can be viewed here.

[jbinda]

LGTM