fix: do case-sensitive search when creating clips

[naveensingh]

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• Switched to case-sensitive search when looking for existing duplicate clips.

Closes the following issue(s)

• Closes Þ and þ cannot both be saved to the pinned clipboard #202

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• All checks are passing.