Simplify BadRequestException error message on insert failure

Replaced the detailed error message for insert failures with only the original exception message from SqlException, removing extra guidance about referenced entities.

src/ReC.Application/Common/Procedures/InsertProcedure/InsertObjectProcedure.cs

@@ -130,10 +130,7 @@ public class InsertObjectProcedureHandler(IRepository repo, SqlExceptionOptions
         catch (SqlException ex)
         {
             if (sqlExceptionOptions.SqlExceptionNumber.Contains(ex.Number))
-                throw new BadRequestException(
-                    $"Insert '{request.Entity}' failed because one or more referenced entities do not exist. " +
-                    "Please verify the supplied identifiers and try again.\n" +
-                    ex.Message, ex);
+                throw new BadRequestException(ex.Message, ex);
             else
                 throw;
         }