Update tootsuite/mastodon Docker tag to v3.4.5 (#17417)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

chart/values.yaml

@@ -8,7 +8,7 @@ image:
   # built from the most recent commit
   #
   # tag: latest
-  tag: v3.4.4
+  tag: v3.4.5
   # use `Always` when using `latest` tag
   pullPolicy: IfNotPresent