Tests

Remove useless imports and fstrings from build-rpm.py #3693

Job	Run time
build-deb	11m 39s
Build and install a Dangerzone RPM on Fedora 39	15m 31s
Build and install a Dangerzone RPM on Fedora 40	11m 34s
macOS	2m 21s
windows	5m 24s
install-deb (ubuntu-20.04, ubuntu, 20.04)	2m 39s
install-deb (ubuntu-22.04, ubuntu, 22.04)	2m 10s
install-deb (ubuntu-23.10, ubuntu, 23.10)	2m 8s
install-deb (ubuntu-24.04, ubuntu, 24.04)	2m 39s
install-deb (debian-bullseye, debian, bullseye)	2m 22s
install-deb (debian-bookworm, debian, bookworm)	2m 36s
install-deb (debian-trixie, debian, trixie)	2m 4s
	1h 3m 7s

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