Skip new read-only storage test on 10.3

[phil-davis]

PR #36397 added the read-only storage feature for 10.4.
The test scenario needs to be skipped when run on 10.3

[codecov]

Codecov Report

Merging #36685 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master   #36685   +/-   ##
=========================================
  Coverage     64.68%   64.68%           
  Complexity    19106    19106           
=========================================
  Files          1269     1269           
  Lines         74728    74728           
  Branches       1320     1320           
=========================================
  Hits          48337    48337           
  Misses        26003    26003           
  Partials        388      388

Flag	Coverage Δ	Complexity Δ
#javascript	54.12% <ø> (ø)	0 <ø> (ø)	⬇️
#phpunit	65.85% <ø> (ø)	19106 <ø> (ø)	⬇️

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