fix: Replace unic-segment with unicode-segmentation in globwatch (#11736)
## Summary
- Replaces unmaintained `unic-segment` 0.9.0 with `unicode-segmentation`
1.12.0 in globwatch
- This eliminates 6 RUSTSEC advisories (the entire unic-* family:
RUSTSEC-2025-0074, 0075, 0080, 0081, 0098, 0104)
- Adapted `GraphemeCursor::new()` call to include the required `true`
parameter for extended grapheme cluster mode
Resolves TURBO-5256