SYNTHMAINT-270 : fix issue with concurrency in tree module (TreeUniqueRootPolicy)

MANDATORY

• Update the workflow of the JIRA ticket
• Fill in the description of the JIRA ticket using the following template

h2. Dépendance(s) externe(s)
h2. Description
h2. Solution technique (présentée en commission technique)

• Fill in the example map section of the JIRA ticket
• Merge or rebase the current branch with sprint (example : git rebase -i 3.11/sprint)
• All tests should pass (all unit tests and end to end tests)

IF NECESSARY

• Update the end_to_end_tests submodule
• Add or update Confluence documentation
• Update the next release page : https://moviplus.atlassian.net/wiki/spaces/SYN/pages/287342640/Prochaine+version