dh_installchangelogs: Generate separate binNMU changelog also under --no-trim (Closes: #1059395)

Gioele Barabuccirequested to merge
gioele/debhelper:chlogs-fix-binnmu-notrim into main

After commit af652db0 the --no-trim logic bypassed the handling of binNMU packages.

Avoiding the early return ensures that the special treatment given to binNMU applies to both trimmed and untrimmed changelogs.

Closes: #1059395

Merge request reports