fix(ci): use --reuse-values instead of --reset-then-reuse-values

helm 4.1 in alpine/helm:4.1 errored 'release: already exists' on the latter
flag despite the release being deployed. --reuse-values is the older,
universally-supported variant — preserves the other service's image tag
between pipeline runs the same way.

.woodpecker/backend.yaml

@@ -54,7 +54,7 @@ steps:
       - |
         helm upgrade --install marktvogt ./helm/marktvogt/ \
           --namespace tenant-2 \
-          --reset-then-reuse-values \
+          --reuse-values \
           --set backend.image.tag="${CI_COMMIT_SHA:0:8}" \
           --rollback-on-failure \
           --wait=watcher \

.woodpecker/web.yaml

@@ -60,7 +60,7 @@ steps:
       - |
         helm upgrade --install marktvogt ./helm/marktvogt/ \
           --namespace tenant-2 \
-          --reset-then-reuse-values \
+          --reuse-values \
           --set web.image.tag="${CI_COMMIT_SHA:0:8}" \
           --rollback-on-failure \
           --wait=watcher \