Accept empty resource paths in linked objects when storing

[greschd]

The .store() method contains a check that all linked objects are
within the same model. However, this check falsely raised when
given an empty resource path. This is now fixed by filtering out
the empty resource paths in the check.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.91%. Comparing base (acee20f) to head (b0678c4).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #569   +/-   ##
=======================================
  Coverage   92.91%   92.91%           
=======================================
  Files          82       82           
  Lines        4291     4292    +1     
=======================================
+ Hits         3987     3988    +1     
  Misses        304      304           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.