Don't double-count sparse truncation fidelity loss

The fidelity tracker was previously counting the fidelity loss roughly twice when there was both amplitude flooring and truncation to memory footprint during Compose(). This has been fixed.

Full Changelog: vm6502q.v9.30.1...vm6502q.v9.30.2

sha1sum results:
d2135ea4105a515db83de5eb6df51383a3f1e593 libqrack-macosx_14_0_arm64.zip
d2c602fff3cac49fa07fcaca3f8feeb851dfc161 libqrack-macosx_15_0_arm64.zip
bb2e4273aa30d982fc4872829ce1d1ee180c283c libqrack-manylinux_2_35_x86_64.zip
74e6438ac7e33ebbd57992589125952957122fc2 libqrack-manylinux_2_39_x86_64.zip
c47b6e84d2c6759455b3f4b1b59af44d712adaf6 libqrack-win-amd64.zip