github-ci: add schema tests to docs workflow

[jasonish]

This will run the schema tests when no code has been modified.

[suricata-qa]

Information: QA skipped due to no C or rust code changed detected. Set to force a run.

Pipeline = code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.16%. Comparing base (a9eee5d) to head (e8c5997).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #14339   +/-   ##
=======================================
  Coverage   84.16%   84.16%           
=======================================
  Files        1012     1012           
  Lines      261904   261904           
=======================================
+ Hits       220439   220440    +1     
+ Misses      41465    41464    -1     

Flag	Coverage Δ
fuzzcorpus	63.30% <ø> (+<0.01%)	⬆️
livemode	18.76% <ø> (+0.02%)	⬆️
pcap	44.62% <ø> (+<0.01%)	⬆️
suricata-verify	64.92% <ø> (-0.03%)	⬇️
unittests	59.21% <ø> (ø)

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