[Fixes #10464] Fix code scanning alert - Uncontrolled data used in path expression

[afabiani]

References: #10464

Checklist

Reviewing is a process done by project maintainers, mostly on a volunteer basis. We try to keep the overhead as small as possible and appreciate if you help us to do so by completing the following items. Feel free to ask in a comment if you have troubles with any of them.

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The following are required only for core and extension modules (they are welcomed, but not required, for contrib modules):

• There is a ticket in https://github.com/GeoNode/geonode/issues describing the issue/improvement/feature (a notable exemption is, changes not visible to end-users)
• The issue connected to the PR must have Labels and Milestone assigned
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• Commit message must be in the form "[Fixes #<issue_number>] Title of the Issue"
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• Commits adding new texts do use gettext and have updated .po / .mo files (without location infos)

Submitting the PR does not require you to check all items, but by the time it gets merged, they should be either satisfied or inapplicable.

[codecov]

Codecov Report

Merging #10465 (d385d16) into master (348291d) will increase coverage by 0.01%.
The diff coverage is 94.28%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #10465      +/-   ##
==========================================
+ Coverage   61.95%   61.97%   +0.01%     
==========================================
  Files         827      827              
  Lines       50904    50937      +33     
  Branches     6551     6556       +5     
==========================================
+ Hits        31538    31568      +30     
- Misses      17683    17687       +4     
+ Partials     1683     1682       -1