Fix tap target value formatting

[aednlaxer]

This pull request fixes formatting of required tap area size by rounding it up to two decimal places.

Before:

Tap area of 33.3333333333x16.66666666667 is too small

After:

Tap area of 33.33x16.67 is too small

[codecov[bot]]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage :thumbsup:

Coverage data is based on head (996b78e) compared to base (0e66877). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #24 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 8 8 Lines 282 286 +4 ========================================= + Hits 282 286 +4 ``` | [Impacted Files](https://codecov.io/gh/rebelappstudio/accessibility_tools/pull/24?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=rebelappstudio) | Coverage Δ | | |---|---|---| | [lib/src/checkers/minimum\_tap\_area\_checker.dart](https://codecov.io/gh/rebelappstudio/accessibility_tools/pull/24?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=rebelappstudio#diff-bGliL3NyYy9jaGVja2Vycy9taW5pbXVtX3RhcF9hcmVhX2NoZWNrZXIuZGFydA==) | `100.00% <100.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=rebelappstudio). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=rebelappstudio)

:umbrella: View full report at Codecov.
:loudspeaker: Do you have feedback about the report comment? Let us know in this issue.

[jpsiitonen]

LGTM