feat: Add no brace parse & show braket flag

[flexboni]

Description

Normarlly Latex foramt not use '{..}' (ex. Not! {x}^2, Like!!! x^2) So i add additional parsing logic that don't have brace. And Pass 'showBracket' parameter to Controller, Switch show braket in Textfield

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Checklist

Remove If [...] items that do not apply to your PR.

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [ ] I linked all related issues and PRs I could find (no links if there are none).
• [ ] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [ ] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [ ] If there is new functionality in code, I added tests covering all my additions.
• [ ] All required checks pass.

[edhom]

@flexboni Thanks for your contribution:) If I remember correctly, we needed the additional parenthesis in order to keep the right precedence. Are you sure they can be safely removed? If so, I would not even give the option to showBrackets...