bottom sheet with text input style option enabled

[rohitbhoite]

:scroll: Description

Added option to enable users to provide custom text input styles.

:bulb: Motivation and Context

:green_heart: How did you test it?

:pencil: Checklist

• [x] I reviewed submitted code
• [ ] I added tests to verify changes
• [x] I updated the docs if needed
• [x] All tests passing
• [x] No breaking changes

:crystal_ball: Next steps

[codecov[bot]]

Codecov Report

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

Comparison is base (7bde416) 83.70% compared to head (34f013a) 83.72%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #248 +/- ## ========================================== + Coverage 83.70% 83.72% +0.02% ========================================== Files 20 20 Lines 632 633 +1 ========================================== + Hits 529 530 +1 Misses 103 103 ``` | [Files](https://app.codecov.io/gh/ueman/feedback/pull/248?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jonas+Uek%C3%B6tter) | Coverage Δ | | |---|---|---| | [...back/lib/src/feedback\_builder/string\_feedback.dart](https://app.codecov.io/gh/ueman/feedback/pull/248?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jonas+Uek%C3%B6tter#diff-ZmVlZGJhY2svbGliL3NyYy9mZWVkYmFja19idWlsZGVyL3N0cmluZ19mZWVkYmFjay5kYXJ0) | `100.00% <100.00%> (ø)` | | | [feedback/lib/src/theme/feedback\_theme.dart](https://app.codecov.io/gh/ueman/feedback/pull/248?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jonas+Uek%C3%B6tter#diff-ZmVlZGJhY2svbGliL3NyYy90aGVtZS9mZWVkYmFja190aGVtZS5kYXJ0) | `86.36% <ø> (ø)` | |

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