components/calendar: fix finding qtpaths' path
Reason for the change
qtpaths is usually installed with a version suffix. Use cmake generator expression to properly locate its path.
Test plan
Screenshots or screen recordings
Bugs fixed
Should fix https://errors.ubuntu.com/problem/7d0d89a54df6feaf88a193788ef93116888bc8b8
migrate-calendar-to-plugin-id.py (FileNotFoundError) /usr/share/kconf_update/migrate-calendar-to-plugin-id.py@13 → init → _execute_child