fix: incorrect grouping of operators in ord function

[666devs]

PR-Codex overview

This PR focuses on correcting the conditional check in the StringUtils.sol file to ensure proper validation of UTF-8 sequences.

Detailed summary

• Modified the conditional statement from if (b & 0xC0 != 0x80) to if ((b & 0xC0) != 0x80).
• This change adds parentheses for clarity and corrects the precedence of the bitwise operation, ensuring accurate UTF-8 sequence validation.

✨ Ask PR-Codex anything about this PR by commenting with /codex {your question}