Update `BaseForm` types

[piotrpospiech]

This resolves #1212.

• Improved getNativeFormProps type in the BaseForm. Added BaseForm props, which weren't omitted in the function.
• Removed placeholder type. Placeholder logic has been removed in the past #1248.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 94.55%. Comparing base (4b3f109) to head (54e4502).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1325 +/- ## ======================================= Coverage 94.55% 94.55% ======================================= Files 231 231 Lines 3823 3823 Branches 1030 1030 ======================================= Hits 3615 3615 Misses 82 82 Partials 126 126 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.