doc: project_roles: Fix table of permissions wrt admin rights

Release engineers do not need and do not have admin rights.
Let's just fix this table removing that cross.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>

Author: aescolar

doc/project/project_roles.rst

@@ -292,7 +292,7 @@ Roles / Permissions
     Supportive Roles QA/Validation                                      x                        x
         ..           DevOps                   **x**
         ..           System Admin             **x**                                      x
-        ..           Release Engineering      **x**      **x**          x
+        ..           Release Engineering                 **x**          x
 
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