fix(MessageBar): Fix IME language handling
Languages that rely on IME keyboards may use the enter key for final text selection on Mac. The MessageBar also uses enter key for submit. The result was that IME input, such as Japanese, was prematurely submitted. I added an additional check for whether the onCompositionEnd event is complete and also added some additional handling for Safari, which is a little bit of a special case. This should resolve the issue on Mac. I manually checked Edge, Chrome, Safari, and Firefox on my machine with a Japanese keyboard.
fix(CodeBlock): Temporarily drop syntax highlighting
Address concern with a sub-dependency in the syntax highlighter. An alternative plan for syntax highlighting is being investigated.