Replace New Tab Menu Match Profiles functionality with regex support

[carlos-zamora]

Summary of the Pull Request

Updates the New Tab Menu's Match Profiles entry to support regex instead of doing a direct match. Also adds validation to ensure the regex is valid. Updated the UI to help make it more clear that this supports regexes and even added a link to some helpful docs.

Validation Steps Performed

✅ Invalid regex displays a warning
✅ Valid regex works nicely

PR Checklist

Closes #18553

[carlos-zamora]

Demo

[lhecker]

This optional-bool code seems like a roundabout way to say "return early if true". 😅

if (!field.empty() && isMatch(field, ...)) {
    return true;
}
if (!field.empty() && isMatch(field, ...)) {
    return true;
}
if (!field.empty() && isMatch(field, ...)) {
    return true;
}
return false;

[lhecker]

AGH! STD REGEX MY MORTAL ENEMY! 😄

That said, regex construction can be fairly costly in general, and we should not treat this as some kind of cheap validation. It involves constructing DFAs, etc., after all. I'm not entirely sure anymore where MatchProfilesEntry fits into the callstack, but seeing that it's also part of TerminalSettingsModel, I'm sure that we can make it cache every regex instance after load and store any warnings into a list. We can then splice its list into the overall SettingsLoadWarnings list (or store it directly there, or something like that). Basically, a way to only construct these once.

FWIW if you want to give icu.h a try:

#include "path/to/buffer/out/UTextAdapter.h"

// Cache this
UErrorCode status = U_ZERO_ERROR;
const auto re = Microsoft::Console::ICU::CreateRegex(pattern, 0, &status);
if (status > U_ZERO_ERROR) {
    // bad regex
}

// Run this
UErrorCode status = U_ZERO_ERROR;
uregex_setText(re.get(), hstring.data(), hstring.size(), &status);
const auto match = uregex_matches(re.get(), 0, &status);
return status == U_ZERO_ERROR && match;