Do not display None on Blade Direction

[Chatewgne]

Description

Related Issue

Checklist

• I have followed the guidelines in our Contributing document
• My code respects the Definition of done available in the Development section of the documentation
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes
• I added an entry in the changelog file
• My commits are all using prefix convention (emoji + tag name) and references associated issues
• I added a label to the PR corresponding to the perimeter of my contribution
• The title of my PR mentionned the issue associated

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.47%. Comparing base (61bf45b) to head (1ccac1d).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4470   +/-   ##
=======================================
  Coverage   98.47%   98.47%           
=======================================
  Files         270      270           
  Lines       21522    21522           
=======================================
  Hits        21193    21193           
  Misses        329      329           

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[cypress]

Geotrek-admin    Run #11083

Run Properties:   Passed #11083  •  e7bdf2d361 ℹ️: Merge 1ccac1d434b917e457ff3b6e5d6882923cca163b into 61bf45bda7d48755f68b36543279...

Project	Geotrek-admin
Branch Review	refs/pull/4470/merge
Run status	Passed #11083
Run duration	02m 05s
Commit	e7bdf2d361 ℹ️: Merge 1ccac1d434b917e457ff3b6e5d6882923cca163b into 61bf45bda7d48755f68b36543279...
Committer	Célia
View all properties for this run ↗︎

---

Test results
Failures	0
Flaky	0
Pending	0
Skipped	0
Passing	22
View all changes introduced in this branch ↗︎