docs(ldap): fix mistake in LDAP authentication documentation

[SilviaSWR]

Checklist

• I have read the contribution guidelines
• One Feature(issus) One PR
• All commits in the PR will be merged into a single commit.
• Add an entry in changelog.en.md if necessary? Don't forget to add your name and github profile link!
• Add / update tests if necessary, Don't missing.
• Add new / update outdated documentation

Description

This PR updates the LDAP authentication documentation to correct outdated information.

fixes #82

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.57%. Comparing base (398db92) to head (75a29ad).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #83   +/-   ##
=======================================
  Coverage   66.57%   66.57%           
=======================================
  Files          26       26           
  Lines        3216     3216           
=======================================
  Hits         2141     2141           
  Misses       1075     1075           

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[SilviaSWR]

This contribution has received funding from the Spanish government (grant EQC2021-007479-P, funded by MCIN/AEI/10.13039/501100011033), the EU NextGeneration/PRTR (PRTR-C17.I1), and the Generalitat de Catalunya.