Make client `updates download` get signed builds if possible #4345

Job	Run time
Pre-commit checks	3m 12s
Build Documentation (f40)	1m 36s
Integration Tests (f40)	8m 43s
Build Documentation (f41)	1m 17s
Integration Tests (f41)	7m 29s
Build Documentation (pip)	3m 3s
Build the RPMS (f40)	4m 31s
Build Documentation (rawhide)	1m 17s
Integration Tests (rawhide)	9m 10s
Build the RPMS (f41)	1m 22s
Unit Tests (f40, bodhi-client)	1m 10s
Build the RPMS (rawhide)	1m 9s
Unit Tests (f40, bodhi-messages)	1m 21s
Unit Tests (f40, bodhi-server)	4m 20s
Unit Tests (f41, bodhi-client)	1m 20s
Unit Tests (f41, bodhi-messages)	1m 1s
Unit Tests (f41, bodhi-server)	3m 51s
Unit Tests (pip, bodhi-client)	3m 0s
Unit Tests (pip, bodhi-messages)	2m 53s
Unit Tests (pip, bodhi-server)	6m 22s
Unit Tests (rawhide, bodhi-client)	1m 9s
Unit Tests (rawhide, bodhi-messages)	1m 32s
Unit Tests (rawhide, bodhi-server)	3m 28s
Diff-cover check	17s
	1h 14m 33s

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